hey guys, i have a derivative question:

f(x) = (x^3 + 2x) e^x

My answer i got was: f'(x) = e^x(3x^2 + 2)
But the book says: f'(x) = e^x(x^3 + 3x^2 + 2x + 2)

Can I get an explanation on how to get the correct answer?

Question

hey guys, i have a derivative question:

f(x) = (x^3 + 2x) e^x

My answer i got was:  f'(x) =  e^x(3x^2 + 2)
But the book says:   f'(x) =  e^x(x^3 + 3x^2 + 2x + 2)

Can I get an explanation on how to get the correct answer?

ankit042 · Answer

you can to apply the product rule f(x)g(x) = g'(x)f(x)+f'(x)g(x)

anonymous · Answer

.,
ohhhh

anonymous · Answer

um does that only apply to exponential functions?

anonymous · Answer

sorry i think i dozed off during class.

ankit042 · Answer

No it is true for all expressions of type f(x).g(x)

anonymous · Answer

thanks a lot ankit

ankit042 · Answer

No problem!

anonymous · Answer

you could also multiply out and then take the derivative
still need the product rule though

anonymous · Answer

ya i see ty