y=csc(x^2)

Ok on this one I know you use the chain rule? The formula for csc is -cscu cotu du/dx so should it go somthing like

------>y'= -csc(x^2) cot(x^2) (2x) ???

also on

f(x)=tan^3x

can I rewrite it to

-----> f(x)= (tan x)^3

f '(x)= 3(sec^2 x)^2 (1)

Any help would be great.