I need help withe equation

I need help withe equation

Differentiate.

f(x) = 3xex csc x

An elastic band is hung on a hook and a mass is hung on the lower end of the band. When the mass is pulled downward and then released, it vibrates vertically. The equation of motion is 

s = 3 cos t + 9 sin t, t ≥ 0,

 where 
s is measured in centimeters and 
t in seconds. (Take the positive direction to be downward.)

(a) Find the velocity and acceleration at time t.

Simplify the trigonometric expression.

 csc^2 x-1 /csc^2 x