Calculus Examples

$\int - e^{- x} d x$

Step 1

Since $- 1$ is constant with respect to $x$ , move $- 1$ out of the integral.

$- \int e^{- x} d x$

Step 2

Let $u = - x$ . Then $d u = - d x$ , so $- d u = d x$ . Rewrite using $u$ and $d$ $u$ .

Tap for more steps...

Step 2.1

Let $u = - x$ . Find $\frac{d u}{d x}$ .

Tap for more steps...

Step 2.1.1

Differentiate $- x$ .

$\frac{d}{d x} [- x]$

Step 2.1.2

Since $- 1$ is constant with respect to $x$ , the derivative of $- x$ with respect to $x$ is $- \frac{d}{d x} [x]$ .

$- \frac{d}{d x} [x]$

Step 2.1.3

Differentiate using the Power Rule which states that $\frac{d}{d x} [x^{n}]$ is $n x^{n - 1}$ where $n = 1$ .

$- 1 \cdot 1$

Step 2.1.4

Multiply $- 1$ by $1$ .

$- 1$

Step 2.2

Rewrite the problem using $u$ and $d u$ .

$- \int - e^{u} d u$

Step 3

Since $- 1$ is constant with respect to $u$ , move $- 1$ out of the integral.

$- - \int e^{u} d u$

Step 4

Simplify.

Tap for more steps...

Step 4.1

Multiply $- 1$ by $- 1$ .

$1 \int e^{u} d u$

Step 4.2

Multiply $\int e^{u} d u$ by $1$ .

$\int e^{u} d u$

Step 5

The integral of $e^{u}$ with respect to $u$ is $e^{u}$ .

$e^{u} + C$

Step 6

Replace all occurrences of $u$ with $- x$ .

$e^{- x} + C$