# Math Help - Difficulty with derivative

1. ## Difficulty with derivative

4. Find derivatives of the functions (do not simplify the answer).

b) f(x) = e^x^2 (x^2+1) + x^4 ( 2^x+1)

I'm having trouble with this, mainly the last term with x as the exponent. Please help.

2. Originally Posted by thekrown
4. Find derivatives of the functions (do not simplify the answer).

b) f(x) = e^x^2 (x^2+1) + x^4 ( 2^x+1)

I'm having trouble with this, mainly the last term with x as the exponent. Please help.

Remember that

$\frac{d}{dx}2^x=\ln(2)\cdot 2^x$

P.S I can ever remember that so I remember this identity instead

$a^x=e^{\ln(a^x)}=e^{x\ln(a)}$

and I do remember how to take the derivative of e.

So the last term will have derivative

$4x^3(2^x+1)+x^4(\ln(2)\cdot 2^x)$

3. Where can I find more of these identities? It seems my skills with finding derivatives is strong, but my knowledge of identities is weak.