I don't know if I should post this here or on the algebra forum.

Trying to find the derivative of f (X) = ³√t (t² + 4)

Let ³√t be a

Let (t² + 4) be b

f(X)' = a'b +b'a

a' =⅓t٨-⅔

b' = 2t

thus f(x)' =(⅓t٨-⅔)(t² + 4) + 2t ³√t

or (t²+4/3t٨⅔) +2t*t٨⅓

I do not understand how to get from here to the answer (7t+4)/(3t٨⅔)

Thanks for any help or advice.