Question

Which of the following are equivalent to the function y=3cos x + 2? Check all that apply. (attached below)

I think it is B. and C. is this correct?

Please explain. Thank you!

Answer 1

bear in mind that \(\bf cos(x)\iff cos(-x)\qquad sin\left({\color{red}{ \theta}}+\frac{\pi}{2}\right)=cos({\color{red}{ \theta}})
\\ \quad \\
y=3cos(-x)+2\implies y=3cos(x)+2
\\ \quad \\
y=3sin\left({\color{red}{ x}}+\frac{\pi}{2}\right)+2\implies y=3cos({\color{red}{ x}})+2\)

Answer 2

so..you're correct