23
Chapter 2: Trigonometry Review
Equations of Periodic
Functions
149–154 Choose the equation that describes the
given periodic function.
149.
(A) f
 
(x) = 2 sin(2x)
(B) f
 
(x) = –2 sin(2x)
(C) f
 
(x) = 2 sin(x)
(D) f
 
(x) = 2 sin(πx)
(E) f x
x
( )
sin
=
( )
2
2
π
142. 2 + cos 2x = –3 cos x
143. tan(3x) = –1
144. cos(2x) = cot(2x)
Amplitude, Period, Phase Shift,
and Midline
145–148 Determine the amplitude, the period, the
phase shift, and the midline of the function.
145. f x
x
( )
sin
=
+
( )
1
2
2
π
146. f x
x
( )
cos
= −
−
(
)
1
4
4
π
147. f
 
(x) = 2 – 3 cos(πx – 6)
148. f x
x
( )
sin
= −
+
( )
1
2
1
2
2
π