# derivative of a function

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• May 14th 2008, 07:41 PM
smplease
derivative of a function
Find y' simplifying where possible

y = 2x^3 − 5x + 2e^x − 7lnx

the last bit of this function is really throwing me out not really sure where to start

• May 14th 2008, 07:52 PM
Mathstud28
Quote:

Originally Posted by smplease
Find y' simplifying where possible

y = 2x^3 − 5x + 2e^x − 7lnx

the last bit of this function is really throwing me out not really sure where to start

$f(x)=2x^3-5x+2e^{x}-7\ln(x)$

$f'(x)=6x^2-5+2e^{x}-\frac{7}{x}$

This is because $\frac{D[e^{u(x)}]}{dx}=u'(x)\cdot{e^{u(x)}}$

and $\frac{D[\ln(u(x))]}{dx}=\frac{u'(x)}{u(x)}$