# Help with a Derivative

1. Jul 2, 2012

### communitycoll

1. The problem statement, all variables and given/known data
I need to find the derivative of y = (3e^x) + [4 / x^(1 / 3)].

2. Relevant equations
My book lists the answer as y' = (3e^x) - (4 / 3)x^-(4 / 3).

Is the book incorrect, or is there something more I can do to the problem to get the book's correct answer? Please tell me exactly what it is they do to get the aforementioned answer.

3. The attempt at a solution
I found y' = [(9e^x)(x^(3 / 4)) - 4] / [3x^(3 / 4)]. The same way it's been found here:
http://www.wolframalpha.com/input/?i=derivative+y+=+3e^x+++(4+/+x^(1+/+3))

2. Jul 2, 2012

### LCKurtz

It might help you to simplify the original problem to this before you differentiate$$y = 3e^x +4 x^{-\frac 1 3}$$

3. Jul 2, 2012

### communitycoll

Thanks. I understand now.