Question

Which of the following are equivalent to the function y = 4cos x - 2? Check all that apply.
A. y = -4cos x + 2
B. y = 4sin(x +π/2 ) - 2
C. y = 4sin(x - π/2) - 2
D. y = 4cos(-x) - 2

Answer 1

cos(x)=cos(-x)
so D

Answer 2

just d?

Answer 3

i didnt bother going through the rest but you can and i will check them for you

Answer 4

here i will write down some clues for you
\[\sin(\frac{\pi}{2}-\theta)=\cos(\theta)\]
\[\cos(\frac{\pi}{2}-\theta)=\sin(\theta)\]
\[\sin(-\theta)=-\sin(\theta)\]

Answer 5

so b and c as well?

Answer 6

cosx=sin(pi/2-x)=sin(-x+pi/2)=sin(-[x-pi/2])
=-sin(x-pi/2)
so neither c or b unless c as a negative in front of it