trigonometric ratios and the unit circle mrs. white precalculus 5.2/5.4

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TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

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Page 1: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

TRIGONOMETRIC RATIOS AND THE UNIT CIRCLEMrs. WhitePrecalculus 5.2/5.4

Page 2: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Schedule

Class/Week Topic Class Work Homework

Mon 2/3 The Unit Circle5.2

Complete the Unit Circle Template

Pg 361 # 3 -30 Multiples of 3

Tues 2/4 Exact Values of the Trig Ratios

Examples/Notes Pg. 383 # 3, 14, 18, 22, 34, 39, 43, 54

Wed 2/5 Exact Values of the Trig Ratios

Review and PracticeWorksheet 5.2(No calculator)

Study for Quiz 5.2

Thurs 2/6 Exact Values of the Trig Ratios

Quiz(No Calculator)

Watch Video on Graphs of

Sine/Cosine

Fri 2/7

Page 3: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Trig Ratios and the Unit Circle

Goals Students should be able to

calculate the exact value of the 6 trigonometric ratios.

Page 4: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Review – Complete the Table

Θ (degrees)

0o 30o 45o 60o 90o

Θ (radians)

0 π/6 π/4 π/3 π/2

sin Θ 0 1

cos Θ 1 0

tan Θ 0 1 Undefined

csc Θ Undefined 1

sec Θ 1 Undefined

cot Θ Undefined 0

Page 5: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Example 1

Plot P (-12, -5) in the coordinate plane. If the terminal side of an angle in standard position passes through P, find the 6 trig. Ratios.

5

1312

135

12

sin

cos

tan

Page 6: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Example 2

Plot P (5, -2) in the coordinate plane. If the terminal side of an angle in standard position passes through P, find the 6 trig. Ratios.

2 29

29

5 29

292

5

sin

cos

tan

Page 7: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Example 3

Given the following, find the 6 trigonometric ratios: sec Θ = -2 sin Θ > 0

3

21

2

3

sin

cos

tan

Page 8: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Example 4

Find the reference angle, α.

Given: Θ = 309o

α = 360o - 309o

α = 51o

Find the reference angle, α.

Given: Θ =

Θ =

α =

11

3

11 2 5

3 1 3

2 5

1 3 3

Page 9: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Example 5

Evaluate the 6 trig functions of the following angles. No Calculator.

Θ = 510°

This is coterminal with: 150° Reference angle: 30°, Quadrant 2

1sin 510

2

3cos 510

2

3tan 510

3

o

o

o

csc 510 2

2 3sec 510

3

cot 510 3

o

o

o

Page 10: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Example 6

Evaluate the 6 trig functions of the following angles. No Calculator.

Θ = This is coterminal with: Reference angle: , Quadrant 3

11

4

3

4

4

11csc 2

411

sec 24

11cot 1

4

11 2sin

4 2

11 2cos

4 211

tan 14

Page 11: TRIGONOMETRIC RATIOS AND THE UNIT CIRCLE Mrs. White Precalculus 5.2/5.4

Example 7

Sketch a right triangle corresponding to the trig function of the acute angle, Θ. Find the length of the missing side (using Pythagorean Th). Evaluate the remaining 5 trig. functions at Θ.

Given: Θ

3sin

2