Pre-Calc Exam Notes 30

# Pre-Calc Exam Notes 30 - 30 Chapter 1 Right Triangle...

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30 Chapter 1 Right Triangle Trigonometry §1.4 negative x -axis. So in Example 1.20, we see that 60 is the reference angle for the nonacute angle θ = 120 ; in Example 1.21, 45 is the reference angle for θ = 225 ; and in Example 1.22, 30 is the reference angle for θ = 330 . Example 1.24 28 x y 0 208 928 Figure 1.4.7 Let θ = 928 . (a) Which angle between 0 and 360 has the same terminal side (and hence the same trigonometric function values) as θ ? (b) What is the reference angle for θ ? Solution: (a) Since 928 = 2 × 360 + 208 , then θ has the same ter- minal side as 208 , as in Figure 1.4.7. (b) 928 and 208 have the same terminal side in QIII, so the refer- ence angle for θ = 928 is 208 180 = 28 . Example 1.25 Suppose that cos θ =− 4 5 . Find the exact values of sin θ and tan θ . Solution: We can use a method similar to the one used to solve Example 1.8 in Section 1.2. That is, draw a right triangle and interpret cos
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## This note was uploaded on 01/21/2012 for the course MAC 1130 taught by Professor Dr.cheun during the Fall '11 term at FSU.

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