Evaluating Trigonometric Functions



4.4 (Day 4) Evaluating Trigonometric Functions

Use the MODE key on your calculator to choose DEGREES or RADIANS.

Find each value. Round your answers to three decimal places.

sin (250°) =

Use degrees and type: sin(250) Enter

tan (-95°) =

cos 36°50’ 25” =

cot 239° = [pic] =

csc 36° 50’ 25” = [pic] =

______________________________________________________________________________

[pic] =

Use radians and type: sin(π [pic] 8) Enter

[pic] = [pic] =

TURN->>>

Ex. Find values of [pic], to three decimal places (in degrees), where [pic]

(a) [pic]

First find the reference angle (first quadrant) by typing

[pic]

[pic]

Then store [pic] by typing .

Ask yourself: “Where is the cosine positive?”

The cosine is positive in quadrants I and IV. [pic] is your quadrant I answer.

To get quadrant IV, type .

[pic] = 22.089° in quadrant I and [pic] = 337.911° in quadrant IV.

(b) [pic]

First find the reference angle by typing

and store in .

(Do not type the negative sign; your reference angle is always in quadrant I.)

[pic]

[pic] (this is stored in A)

Ask yourself: “Where is the sine negative?”

The sine is negative in quadrants III and IV.

To get quadrant III, type .

To get quadrant IV, type .

[pic] = 217.582° in quadrant III and [pic] = 322.418° in quadrant IV.

-----------------------

2nd

cos

.9266

Enter

STO

Alpha

A

360

-

Alpha

A

[pic]

[pic]

[pic]

[pic]

Enter

0.60999

sin

2nd

A

A

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óèÝóÔÝȽݲȲ¦›Œ€th›\›Ý›Ý›t¦›ÝŒ€Œt›Œ€hh?PÎ>*[pic]OJQJhCJOJQJaJh?PÎCJOJQJaJhCJOJQJaJh?PÎh?PÎCJOJQJAlpha

+

180

A

Alpha

-

360

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