2.3 Finding Trigonometric Function Values Using a Calculator

2.3

Finding Trigonometric Function

Values Using a Calculator

? Differentiate between exact and approximate values.

? Find approximate values of trig functions.

? Find approximate values of angles given the approximate

value of the function.

? Find approximate values of obtuse angles.

? Calculate grade resistance.

Copyright ? 2009 Pearson Addison-Wesley

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Caution

When evaluating trigonometric

functions of angles given in degrees,

remember that the calculator must

be set in degree mode.

Copyright ? 2009 Pearson Addison-Wesley

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Exact vs. Approximate Values

Exact values of trig functions are values that can

not be found with most calculators.

Example:

Approximate values of trig functions are values

that can be found with a calculator.

Example:

Copyright ? 2009 Pearson Addison-Wesley

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Example 1

FINDING FUNCTION VALUES WITH A

CALCULATOR

Approximate the value of each expression.

(a) sin 49¡ã12¡ä

¡Ö .75699506

(b) sec 97.977¡ã

Calculators do not have a secant

key, so first find cos 97.977¡ã and

then take the reciprocal.

sec 97.977¡ã ¡Ö ¨C7.2059

Copyright ? 2009 Pearson Addison-Wesley

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Example 1

FINDING FUNCTION VALUES WITH A

CALCULATOR (continued)

Approximate the value of each expression.

(c)

1

cot 51.4283¡ã

= tan 51.4283¡ã ¡Ö 1.25394815

(d) sin (¨C246¡ã) ¡Ö ¨C.91354546

¡ä

e csc ?14¡ã18 44

Copyright ? 2009 Pearson Addison-Wesley

¡ä¡ä

1

=

¡Ö ?4.0452

¡ä

¡ä¡ä

sin(?14¡ã18 44 )

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