1. ## trig question

I need help if any one has suggestions

y=sin (3x+ pi/2)

2. Originally Posted by besito2001
I need help if any one has suggestions

y=sin (3x+ pi/2)
$sin(A+B) = sinA.cosB + cosA.sinB$
so if you substitute $A=3x$ and $B= \frac{\pi}{2}$,
you have $y=cos(3x)$