check my 2 answers?

Hey...it looks like nothing has appeared in the question...maybe something is wrong?

First one  ....correct  !!!

Second one

Notice  that  we  can write this as  :

f(x)  =  Asin B(x - C) + D

f(x)  =  33 sin 7 (x  -  pi/84) + 33

Only B affects the period......

"B"  tells us how many periods are in 2pi sec

So  we can find the period (in sec)  thusly :

B =   2pi / period

7  = 2pi / period      rearrange as

period  =  2pi/7  ≈  .897 sec  =  .90  sec   →  correct  !!!!