Integral of e⁻ˣ

∫e−x dx=−e−x+C\int e^{-x}\,dx = -e^{-x} + C

Reverse chain rule: divide by the inner slope −1. The area from 0 to ∞ is exactly 1.

Step by step

  1. Exponential rule

    ∫eᵘ du = eᵘ. Divide by the inner slope -1 (reverse chain rule).

    ∫e−x dx=−e−x\int e^{-x}\,dx = -e^{-x}
-1-0.50.511.522.533.540.511.522.53
  • f(x) = e⁻ˣ
  • F(x) + C

Every choice of C gives a valid antiderivative, since shifting up or down doesn’t change the slope.

Open in the integral calculator

Questions students ask

What is the integral of e⁻ˣ?

∫e−x dx=−e−x+C\int e^{-x}\,dx = -e^{-x} + C.

How do you integrate e⁻ˣ?

Reverse chain rule: divide by the inner slope −1. The area from 0 to ∞ is exactly 1.

How can I check the answer?

Differentiate it: the derivative of −e−x-e^{-x} is e−xe^{-x}. CalcViz checks every antiderivative this way before showing it.