Hi

Your answer is not correct because your minimum is -4 and your maximum is 4

The mean value is (7+(-1))/2 = 3 = number to be added to sine

The amplitude is max-mean = mean-min = 7 - 3 = 3 - (-1) = 4 = factor of sine

The period is pi/2 therefore sine is applied to (4x + phi) because

sin(4(x+pi/2) + phi) = sin(4x + 2pi + phi) = sin(4x + phi)

The phase shift is phi = 3pi/4

The function is therefore : 3 + 4sin(4x+3pi/4)