Dr. William Murray teaches Educator's Trigonometry course covering Functions, Identities, Applications, and Complex/Polar Coordinates. Educated at UC Berkeley (Ph.D) and Georgetown (B.S.), Professor Murray returns to the class that made him fall in love with mathematics. He will guide you through topics such as the Pythagorean Identity, Inverse Trigonometric Functions, Law of Sines, Law of Cosines, Trigonometric Word Problems, Vectors, and end with Polar Coordinates. This course is essential to those having trouble with trigonometry in any setting as Wills course meets or exceeds all state standards. Each video lecture is accompanied by several worked-out video examples and QuickNotes to help summarize each topic.
| I. Trigonometric Functions |
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Angles |
39:05 |
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Intro |
0:00 | |
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Degrees |
0:22 | |
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| Circle is 360 Degrees |
0:48 | |
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| Splitting a Circle |
1:13 | |
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Radians |
2:08 | |
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| Circle is 2 Pi Radians |
2:31 | |
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| One Radian |
2:52 | |
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| Half-Circle and Right Angle |
4:00 | |
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Converting Between Degrees and Radians |
6:24 | |
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| Formulas for Degrees and Radians |
6:52 | |
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Coterminal, Complementary, Supplementary Angles |
7:23 | |
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| Coterminal Angles |
7:30 | |
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| Complementary Angles |
9:40 | |
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| Supplementary Angles |
10:08 | |
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Example 1: Dividing a Circle |
10:38 | |
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Example 2: Converting Between Degrees and Radians |
11:56 | |
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Example 3: Quadrants and Coterminal Angles |
14:18 | |
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Extra Example 1: Common Angle Conversions |
8:02 | |
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Extra Example 2: Quadrants and Coterminal Angles |
7:14 | |
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Sine and Cosine Functions |
43:16 |
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Intro |
0:00 | |
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Sine and Cosine |
0:15 | |
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| Unit Circle |
0:22 | |
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| Coordinates on Unit Circle |
1:03 | |
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| Right Triangles |
1:52 | |
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| Adjacent, Opposite, Hypotenuse |
2:25 | |
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| Master Right Triangle Formula: SOHCAHTOA |
2:48 | |
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Odd Functions, Even Functions |
4:40 | |
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| Example: Odd Function |
4:56 | |
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| Example: Even Function |
7:30 | |
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Example 1: Sine and Cosine |
10:27 | |
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Example 2: Graphing Sine and Cosine Functions |
14:39 | |
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Example 3: Right Triangle |
21:40 | |
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Example 4: Odd, Even, or Neither |
26:01 | |
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Extra Example 1: Right Triangle |
4:05 | |
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Extra Example 2: Graphing Sine and Cosine Functions |
5:23 | |
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Sine and Cosine Values of Special Angles |
33:05 |
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Intro |
0:00 | |
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45-45-90 Triangle and 30-60-90 Triangle |
0:08 | |
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| 45-45-90 Triangle |
0:21 | |
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| 30-60-90 Triangle |
2:06 | |
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Mnemonic: All Students Take Calculus (ASTC) |
5:21 | |
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| Using the Unit Circle |
5:59 | |
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| New Angles |
6:21 | |
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| Other Quadrants |
9:43 | |
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| Mnemonic: All Students Take Calculus |
10:13 | |
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Example 1: Convert, Quadrant, Sine/Cosine |
13:11 | |
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Example 2: Convert, Quadrant, Sine/Cosine |
16:48 | |
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Example 3: All Angles and Quadrants |
20:21 | |
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Extra Example 1: Convert, Quadrant, Sine/Cosine |
4:15 | |
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Extra Example 2: All Angles and Quadrants |
4:03 | |
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Modified Sine Waves: Asin(Bx+C)+D and Acos(Bx+C)+D |
52:03 |
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Intro |
0:00 | |
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Amplitude and Period of a Sine Wave |
0:38 | |
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| Sine Wave Graph |
0:58 | |
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| Amplitude: Distance from Middle to Peak |
1:18 | |
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| Peak: Distance from Peak to Peak |
2:41 | |
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Phase Shift and Vertical Shift |
4:13 | |
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| Phase Shift: Distance Shifted Horizontally |
4:16 | |
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| Vertical Shift: Distance Shifted Vertically |
6:48 | |
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Example 1: Amplitude/Period/Phase and Vertical Shift |
8:04 | |
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Example 2: Amplitude/Period/Phase and Vertical Shift |
17:39 | |
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Example 3: Find Sine Wave Given Attributes |
25:23 | |
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Extra Example 1: Amplitude/Period/Phase and Vertical Shift |
7:27 | |
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Extra Example 2: Find Cosine Wave Given Attributes |
10:27 | |
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Tangent and Cotangent Functions |
36:04 |
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Intro |
0:00 | |
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Tangent and Cotangent Definitions |
0:21 | |
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| Tangent Definition |
0:25 | |
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| Cotangent Definition |
0:47 | |
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Master Formula: SOHCAHTOA |
1:01 | |
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| Mnemonic |
1:16 | |
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Tangent and Cotangent Values |
2:29 | |
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| Remember Common Values of Sine and Cosine |
2:46 | |
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| 90 Degrees Undefined |
4:36 | |
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Slope and Menmonic: ASTC |
5:47 | |
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| Uses of Tangent |
5:54 | |
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| Example: Tangent of Angle is Slope |
6:09 | |
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| Sign of Tangent in Quadrants |
7:49 | |
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Example 1: Graph Tangent and Cotangent Functions |
10:42 | |
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Example 2: Tangent and Cotangent of Angles |
16:09 | |
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Example 3: Odd, Even, or Neither |
18:56 | |
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Extra Example 1: Tangent and Cotangent of Angles |
2:27 | |
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Extra Example 2: Tangent and Cotangent of Angles |
5:02 | |
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Secant and Cosecant Functions |
27:18 |
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Intro |
0:00 | |
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Secant and Cosecant Definitions |
0:17 | |
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| Secant Definition |
0:18 | |
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| Cosecant Definition |
0:33 | |
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Example 1: Graph Secant Function |
0:48 | |
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Example 2: Values of Secant and Cosecant |
6:49 | |
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Example 3: Odd, Even, or Neither |
12:49 | |
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Extra Example 1: Graph of Cosecant Function |
4:58 | |
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Extra Example 2: Values of Secant and Cosecant |
5:19 | |
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Inverse Trigonometric Functions |
32:58 |
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Intro |
0:00 | |
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Arcsine Function |
0:24 | |
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| Restrictions between -1 and 1 |
0:43 | |
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| Arcsine Notation |
1:26 | |
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Arccosine Function |
3:07 | |
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| Restrictions between -1 and 1 |
3:36 | |
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| Cosine Notation |
3:53 | |
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Arctangent Function |
4:30 | |
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| Between -Pi/2 and Pi/2 |
4:44 | |
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| Tangent Notation |
5:02 | |
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Example 1: Domain/Range/Graph of Arcsine |
5:45 | |
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Example 2: Arcsin/Arccos/Arctan Values |
10:46 | |
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Example 3: Domain/Range/Graph of Arctangent |
17:14 | |
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Extra Example 1: Domain/Range/Graph of Arccosine |
4:30 | |
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Extra Example 2: Arcsin/Arccos/Arctan Values |
5:40 | |
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Computations of Inverse Trigonometric Functions |
31:08 |
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Intro |
0:00 | |
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Inverse Trigonometric Function Domains and Ranges |
0:31 | |
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| Arcsine |
0:41 | |
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| Arccosine |
1:14 | |
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| Arctangent |
1:41 | |
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Example 1: Arcsines of Common Values |
2:44 | |
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Example 2: Odd, Even, or Neither |
5:57 | |
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Example 3: Arccosines of Common Values |
12:24 | |
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Extra Example 1: Arctangents of Common Values |
5:50 | |
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Extra Example 2: Arcsin/Arccos/Arctan Values |
8:51 | |
| II. Trigonometric Identities |
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Pythagorean Identity |
19:11 |
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Intro |
0:00 | |
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Pythagorean Identity |
0:17 | |
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| Pythagorean Triangle |
0:27 | |
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| Pythagorean Identity |
0:45 | |
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Example 1: Use Pythagorean Theorem to Prove Pythagorean Identity |
1:14 | |
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Example 2: Find Angle Given Cosine and Quadrant |
4:18 | |
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Example 3: Verify Trigonometric Identity |
8:00 | |
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Extra Example 1: Use Pythagorean Identity to Prove Pythagorean Theorem |
3:32 | |
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Extra Example 2: Find Angle Given Cosine and Quadrant |
3:55 | |
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Identity Tan(squared)x+1=Sec(squared)x |
23:16 |
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Intro |
0:00 | |
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Main Formulas |
0:19 | |
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| Companion to Pythagorean Identity |
0:27 | |
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| For Cotangents and Cosecants |
0:52 | |
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| How to Remember |
0:58 | |
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Example 1: Prove the Identity |
1:40 | |
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Example 2: Given Tan Find Sec |
3:42 | |
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Example 3: Prove the Identity |
7:45 | |
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Extra Example 1: Prove the Identity |
2:22 | |
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Extra Example 2: Given Sec Find Tan |
4:34 | |
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Addition and Subtraction Formulas |
52:52 |
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Intro |
0:00 | |
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Addition and Subtraction Formulas |
0:09 | |
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| How to Remember |
0:48 | |
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Cofunction Identities |
1:31 | |
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| How to Remember Graphically |
1:44 | |
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| Where to Use Cofunction Identities |
2:52 | |
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Example 1: Derive the Formula for cos(A-B) |
3:08 | |
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Example 2: Use Addition and Subtraction Formulas |
16:03 | |
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Example 3: Use Addition and Subtraction Formulas to Prove Identity |
25:11 | |
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Extra Example 1: Use cos(A-B) and Cofunction Identities |
7:54 | |
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Extra Example 2: Convert to Radians and use Formulas |
11:32 | |
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Double Angle Formulas |
29:05 |
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Intro |
0:00 | |
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Main Formula |
0:07 | |
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| How to Remember from Addition Formula |
0:18 | |
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| Two Other Forms |
1:35 | |
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Example 1: Find Sine and Cosine of Angle using Double Angle |
3:16 | |
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Example 2: Prove Trigonometric Identity using Double Angle |
9:37 | |
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Example 3: Use Addition and Subtraction Formulas |
12:38 | |
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Extra Example 1: Find Sine and Cosine of Angle using Double Angle |
6:10 | |
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Extra Example 2: Prove Trigonometric Identity using Double Angle |
3:18 | |
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Half-Angle Formulas |
43:55 |
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Intro |
0:00 | |
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Main Formulas |
0:09 | |
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| Confusing Part |
0:34 | |
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Example 1: Find Sine and Cosine of Angle using Half-Angle |
0:54 | |
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Example 2: Prove Trigonometric Identity using Half-Angle |
11:51 | |
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Example 3: Prove the Half-Angle Formula for Tangents |
18:39 | |
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Extra Example 1: Find Sine and Cosine of Angle using Half-Angle |
7:16 | |
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Extra Example 2: Prove Trigonometric Identity using Half-Angle |
3:34 | |
| III. Applications of Trigonometry |
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Trigonometry in Right Angles |
25:43 |
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Intro |
0:00 | |
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Master Formula for Right Angles |
0:11 | |
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| SOHCAHTOA |
0:15 | |
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| Only for Right Triangles |
1:26 | |
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Example 1: Find All Angles in a Triangle |
2:19 | |
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Example 2: Find Lengths of All Sides of Triangle |
7:39 | |
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Example 3: Find All Angles in a Triangle |
11:00 | |
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Extra Example 1: Find All Angles in a Triangle |
5:10 | |
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Extra Example 2: Find Lengths of All Sides of Triangle |
4:18 | |
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Law of Sines |
56:40 |
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Intro |
0:00 | |
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Law of Sines Formula |
0:18 | |
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| SOHCAHTOA |
0:27 | |
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| Any Triangle |
0:59 | |
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| Graphical Representation |
1:25 | |
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| Solving Triangle Completely |
2:37 | |
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When to Use Law of Sines |
2:55 | |
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| ASA, SAA, SSA, AAA |
2:59 | |
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| SAS, SSS for Law of Cosines |
7:11 | |
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Example 1: How Many Triangles Satisfy Conditions, Solve Completely |
8:44 | |
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Example 2: How Many Triangles Satisfy Conditions, Solve Completely |
15:30 | |
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Example 3: How Many Triangles Satisfy Conditions, Solve Completely |
28:32 | |
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Extra Example 1: How Many Triangles Satisfy Conditions, Solve Completely |
8:01 | |
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Extra Example 2: How Many Triangles Satisfy Conditions, Solve Completely |
15:11 | |
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Law of Cosines |
49:05 |
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Intro |
0:00 | |
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Law of Cosines Formula |
0:23 | |
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| Graphical Representation |
0:34 | |
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| Relates Sides to Angles |
1:00 | |
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| Any Triangle |
1:20 | |
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| Generalization of Pythagorean Theorem |
1:32 | |
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When to Use Law of Cosines |
2:26 | |
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| SAS, SSS |
2:30 | |
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Heron's Formula |
4:49 | |
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| Semiperimeter S |
5:11 | |
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Example 1: How Many Triangles Satisfy Conditions, Solve Completely |
5:53 | |
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Example 2: How Many Triangles Satisfy Conditions, Solve Completely |
15:19 | |
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Example 3: Find Area of a Triangle Given All Side Lengths |
26:33 | |
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Extra Example 1: How Many Triangles Satisfy Conditions, Solve Completely |
11:05 | |
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Extra Example 2: Length of Third Side and Area of Triangle |
9:17 | |
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Finding the Area of a Triangle |
27:37 |
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Intro |
0:00 | |
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Master Right Triangle Formula and Law of Cosines |
0:19 | |
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| SOHCAHTOA |
0:27 | |
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| Law of Cosines |
1:23 | |
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Heron's Formula |
2:22 | |
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| Semiperimeter S |
2:37 | |
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Example 1: Area of Triangle with Two Sides and One Angle |
3:12 | |
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Example 2: Area of Triangle with Three Sides |
6:11 | |
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Example 3: Area of Triangle with Three Sides, No Heron's Formula |
8:50 | |
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Extra Example 1: Area of Triangle with Two Sides and One Angle |
2:54 | |
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Extra Example 2: Area of Triangle with Two Sides and One Angle |
6:48 | |
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Word Problems and Applications of Trigonometry |
34:25 |
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Intro |
0:00 | |
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Formulas to Remember |
0:11 | |
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| SOHCAHTOA |
0:15 | |
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| Law of Sines |
0:55 | |
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| Law of Cosines |
1:48 | |
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| Heron's Formula |
2:46 | |
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Example 1: Telephone Pole Height |
4:01 | |
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Example 2: Bridge Length |
7:48 | |
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Example 3: Area of Triangular Field |
14:20 | |
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Extra Example 1: Kite Height |
4:36 | |
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Extra Example 2: Roads to a Town |
10:34 | |
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Vectors |
46:42 |
| | |
Intro |
0:00 | |
| | |
Vector Formulas and Concepts |
0:12 | |
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| Vectors as Arrows |
0:28 | |
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| Magnitude |
0:38 | |
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| Direction |
0:50 | |
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| Drawing Vectors |
1:16 | |
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| Uses of Vectors: Velocity, Force |
1:37 | |
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| Vector Magnitude Formula |
3:15 | |
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| Vector Direction Formula |
3:28 | |
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| Vector Components |
6:27 | |
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Example 1: Magnitude and Direction of Vector |
8:00 | |
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Example 2: Force to a Box on a Ramp |
12:25 | |
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Example 3: Plane with Wind |
18:30 | |
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Extra Example 1: Components of a Vector |
2:54 | |
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Extra Example 2: Ship with a Current |
13:13 | |
| IV. Complex Numbers and Polar Coordinates |
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Polar Coordinates |
67:35 |
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Intro |
0:00 | |
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Polar Coordinates vs Rectangular/Cartesian Coordinates |
0:12 | |
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| Rectangular Coordinates, Cartesian Coordinates |
0:23 | |
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| Polar Coordinates |
0:59 | |
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Converting Between Polar and Rectangular Coordinates |
2:06 | |
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| R |
2:16 | |
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| Theta |
2:48 | |
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Example 1: Convert Rectangular to Polar Coordinates |
6:53 | |
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Example 2: Convert Polar to Rectangular Coordinates |
17:28 | |
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Example 3: Graph the Polar Equation |
28:00 | |
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Extra Example 1: Convert Polar to Rectangular Coordinates |
10:01 | |
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Extra Example 2: Graph the Polar Equation |
10:53 | |
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Complex Numbers |
35:59 |
| | |
Intro |
0:00 | |
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Main Definition |
0:07 | |
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| Number i |
0:23 | |
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| Complex Number Form |
0:33 | |
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Powers of Imaginary Number i |
1:00 | |
| | |
| Repeating Pattern |
1:43 | |
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Operations on Complex Numbers |
3:30 | |
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| Adding and Subtracting Complex Numbers |
3:39 | |
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| Multiplying Complex Numbers |
4:39 | |
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| FOIL Method |
5:06 | |
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| Conjugation |
6:29 | |
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Dividing Complex Numbers |
7:34 | |
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| Conjugate of Denominator |
7:45 | |
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Example 1: Solve For Complex Number z |
11:02 | |
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Example 2: Expand and Simplify |
15:34 | |
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Example 3: Simplify the Powers of i |
17:50 | |
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Extra Example 1: Simplify |
4:37 | |
| | |
Extra Example 2: All Complex Numbers Satisfying Equation |
10:00 | |
| |
Polar Form of Complex Numbers |
40:43 |
| | |
Intro |
0:00 | |
| | |
Polar Coordinates |
0:49 | |
| | |
| Rectangular Form |
0:52 | |
| | |
| Polar Form |
1:25 | |
| | |
| R and Theta |
1:51 | |
| | |
Polar Form Conversion |
2:27 | |
| | |
| R and Theta |
2:35 | |
| | |
| Optimal Values |
4:05 | |
| | |
| Euler's Formula |
4:25 | |
| | |
Multiplying Two Complex Numbers in Polar Form |
6:10 | |
| | |
| Multiply r's Together and Add Exponents |
6:32 | |
| | |
Example 1: Convert Rectangular to Polar Form |
7:17 | |
| | |
Example 2: Convert Polar to Rectangular Form |
13:49 | |
| | |
Example 3: Multiply Two Complex Numbers |
17:28 | |
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Extra Example 1: Convert Between Rectangular and Polar Forms |
6:48 | |
| | |
Extra Example 2: Simplify Expression to Polar Form |
7:48 | |
| |
DeMoivre's Theorem |
57:37 |
| | |
Intro |
0:00 | |
| | |
Introduction to DeMoivre's Theorem |
0:10 | |
| | |
| n nth Roots |
3:06 | |
| | |
DeMoivre's Theorem: Finding nth Roots |
3:52 | |
| | |
| Relation to Unit Circle |
6:29 | |
| | |
| One nth Root for Each Value of k |
7:11 | |
| | |
Example 1: Convert to Polar Form and Use DeMoivre's Theorem |
8:24 | |
| | |
Example 2: Find Complex Eighth Roots |
15:27 | |
| | |
Example 3: Find Complex Roots |
27:49 | |
| | |
Extra Example 1: Convert to Polar Form and Use DeMoivre's Theorem |
7:41 | |
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Extra Example 2: Find Complex Fourth Roots |
14:36 | |