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This guide explains how to find the values of six trigonometric functions for 300 degrees and how to approximate values using a calculator in degree mode. It covers concepts such as cotangent, secant, sine, cosine, inverse trigonometric functions, and angle measures.
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Warm Up Find the values of the six trigonometric functions for 300
Finding Trigonometric Function Values Using a Calculator Section 2.3 Objective: SWBAT find trig function values using a calculator.
Function Values Using a Calculator • Calculators are capable of finding trigonometric function values. • When evaluating trigonometric functions of angles given in degrees, remember that the calculator must be set in degree mode. • Remember that most calculator values of trigonometric functions are approximations.
a) b) cot 68.4832 Use the identity cot 68.4832 .3942492 Finding Function Values with a CalculatorApproximate the value of each expression.
FINDING FUNCTION VALUES WITH A CALCULATOR • Approximate the value of each expression. (a) sin 49°12′ ≈ .75699506 (b) sec 97.977° Calculators do not have a secant key, so first find cos 97.977° and then take the reciprocal. sec 97.977° ≈ –.75699506
Use the reciprocal identity FINDING FUNCTION VALUES WITH A CALCULATOR • Approximate the value of each expression. (c) ≈ –.91354546 (d) sin (–246°)
Angle Measures Using a Calculator REMEMBER: • Graphing calculators have three inverse functions. • If x is an appropriate number, then gives the measure of an angle whose sine, cosine, or tangent is x.
Using Inverse Trigonometric Functions to Find Angles • Use a calculator to find an angle in the interval that satisfies each condition. Using the degree mode and the inverse sine function, we find that an angle having sine value .8535508 is 58.6 . We write the result as
Using Inverse Trigonometric Functions to Find Angles continued Use the identity Find the reciprocal of 2.48679 to get Now find using the inverse cosine function. The result is 66.289824
Use the identity USING INVERSE TRIGONOMETRIC FUNCTIONS TO FIND ANGLES • Use a calculator to find an angle θ in the interval [0°, 90°] that satisfies each condition. (a) Use degree mode and the inverse sine function. (b)
Homework • Page 64 • # 5-28 evens