Question

How do you find the derivative of `2e^-x`?

Answer 1

`(dy)/(dx)=-2e^-x`

Explanation:

Recall that `d/dxe^x=e^x`

Using chain rule, `(dy)/(dx)=(dy)/(du)*(du)/(dx)`,

Let `u=-x`

`(dy)/(du)=d/(du)2e^u=2e^u=2e^-x`

`(du)/(dx)=d/(dx)-x=-1`

`:.(dy)/(dx)=-1*2e^-x=-2e^-x`