Question

What is the derivative of e to the poker minus x

Answer 1

y =
`e^(-x)`

let u = x

y =
`e^(u)`

dy/dx = dy/du * du/dx

dy/du =
`e^(u)`

du/dx = -1

dy/dx =
`e^(u)` * -1

dy/dx = -
`e^(u)`

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

Answer 2

`(e^(-x))'=e^(-x)\cdot(-x)'=e^(-x)\cdot(-1)=-e^(-x)`