Derivative

Question

Find the derivative of f(x) = x²e^–x

I've managed some of the question but am having trouble finishing it. Can someone please explain?

Answer 1

Hi Iona,

 

f(x)=x², g(x)=e^-x

 

let u=-x, du=-dx, g(u)=e^u, g′(u)=e^udu=> g(x)=-e^-x

 

f′(x)=2x, g′(x)=-e^-x

 

Now use product rule, 2x(e^-x) + x²(-e^-x)

 

I hope this helps