Help 44,45 ​

44.

We have that    y  = Acos (Bθ)

If the max is 4  and the minimun  is -4, the amplitude   =  4  =  A

To find  B, we can solve this

2pi / (2pi / 3)  = B

3 * 2pi  / 2pi  = B

3  = B

So....the function is

y   = 4 cos 3θ

45.  tan  3pi/4   =   - tan pi/4  =    -1