7.5 Values of Trig Functions

Trig Values for Non-special Angles

Use calculator to find value & round to 4 digits* make sure calc is in DEG mode* angle first or cos first depends on calc

cos76.5 0.2334

1cot 295.6 0.4791

tan 295.6

Calc doesn’t have cot but has tan

Ex 1)

Ex 2)

Trig Values for Non-special Angles

3060sin( 401 30 ) sin( (401 ) )

sin( 401.5 ) 0.6626

1csc0.4422 2.3368

sin 0.4422

o o

oChange to decimal degrees

No degree symbol → Radians!!Change mode on calc

Ex 3)

Ex 4)

Ex 5) If 0° ≤ < 360°, find the angle in QI such that , round to nearest tenth degree

Finding Angles

sin 0.6587

Use inverse sin to find 1 1

1

sin (sin ) sin (0.6587)

sin (0.6587)

41.2

angle trig value

Ex 6) If 0 ≤ < 360, find to nearest tenth of a degree if cos = – 0.9641, QIII

1

cos 0.9641

cos (0.9641)

15.4

180 15.4 195.4

QIII

180

First, find the related angle

Change trig value to positive15.4

Ex 7) Find in Q IV to nearest tenth degree such that cot = – 8.028

1

1 1tan

cot 8.0281

tan8.028

7.1

360 7.1 352.9

QIV

Change to (+) for ref angle360

7.1

Homework

#716 Pg. 418 1 – 35 odd