Hey I am just like u I wasn't at school I have been waiting for 1 hour and Noone had answer me I am sad I am going to fail
This is not true.
where is 
is any integer. So suppose we pick some value of 
other than these, say 
. Then
Answer:
y = 4 sin(½ x) − 3
Step-by-step explanation:
The function is either sine or cosine:
y = A sin(2π/T x) + C
y = A cos(2π/T x) + C
where A is the amplitude, T is the period, and C is the midline.
The midline is the average of the min and max:
C = (1 + -7) / 2
C = -3
The amplitude is half the difference between the min and max:
A = (1 − -7) / 2
A = 4
The maximum is at x = π, and the minimum is at x = 3π. The difference, 2π, is half the period. So T = 4π.
Plugging in, the options are:
y = 4 sin(½ x) − 3
y = 4 cos(½ x) − 3
Since the maximum is at x = π, this must be a sine wave.
y = 4 sin(½ x) − 3
