Page 36 - Calculus Demystified

Basics
CHAPTER 1
y 23

5 /6 = 150
/3 = 60

_ _ x
= 180
_ _
3 /4 = 135

Fig. 1.31

y

unit circle P = (x, y)

sin

cos
x

Fig. 1.32

(2) For any number θ,

−1 ≤ cos θ ≤ 1 and − 1 ≤ sin θ ≤ 1.

2
2
2
Math Note: It is common to write sin θ to mean (sin θ) and cos θ to mean
2
(cos θ) .
EXAMPLE 1.18
Compute the sine and cosine of π/3.