Calculus Examples

$\int (x + 4) \sqrt{3 - x} d x$

Step 1

Integrate by parts using the formula $\int u d v = u v - \int v d u$ , where $u = x + 4$ and $d v = \sqrt{3 - x}$ .

$(x + 4) (- \frac{2}{3} {(3 - x)}^{\frac{3}{2}}) - \int - \frac{2}{3} {(3 - x)}^{\frac{3}{2}} d x$

Step 2

Since $- \frac{2}{3}$ is constant with respect to $x$ , move $- \frac{2}{3}$ out of the integral.

$(x + 4) (- \frac{2}{3} {(3 - x)}^{\frac{3}{2}}) - (- \frac{2}{3} \int {(3 - x)}^{\frac{3}{2}} d x)$

Step 3

Let $u = 3 - x$ . Then $d u = - d x$ , so $- d u = d x$ . Rewrite using $u$ and $d$ $u$ .

Tap for more steps...

Step 3.1

Let $u = 3 - x$ . Find $\frac{d u}{d x}$ .

Tap for more steps...

Step 3.1.1

Differentiate $3 - x$ .

$\frac{d}{d x} [3 - x]$

Step 3.1.2

Differentiate.

Tap for more steps...

Step 3.1.2.1

By the Sum Rule, the derivative of $3 - x$ with respect to $x$ is $\frac{d}{d x} [3] + \frac{d}{d x} [- x]$ .

$\frac{d}{d x} [3] + \frac{d}{d x} [- x]$

Step 3.1.2.2

Since $3$ is constant with respect to $x$ , the derivative of $3$ with respect to $x$ is $0$ .

$0 + \frac{d}{d x} [- x]$

Step 3.1.3

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

Tap for more steps...

Step 3.1.3.1

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

$0 - \frac{d}{d x} [x]$

Step 3.1.3.2

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

$0 - 1 \cdot 1$

Step 3.1.3.3

Multiply $- 1$ by $1$ .

$0 - 1$

Step 3.1.4

Subtract $1$ from $0$ .

$- 1$

Step 3.2

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

$(x + 4) (- \frac{2}{3} {(3 - x)}^{\frac{3}{2}}) - (- \frac{2}{3} \int - u^{\frac{3}{2}} d u)$

Step 4

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

$(x + 4) (- \frac{2}{3} {(3 - x)}^{\frac{3}{2}}) - (- \frac{2}{3} (- \int u^{\frac{3}{2}} d u))$

Step 5

By the Power Rule, the integral of $u^{\frac{3}{2}}$ with respect to $u$ is $\frac{2}{5} u^{\frac{5}{2}}$ .

$(x + 4) (- \frac{2}{3} {(3 - x)}^{\frac{3}{2}}) - (- \frac{2}{3} (- (\frac{2}{5} u^{\frac{5}{2}} + C)))$

Step 6

Simplify.

Tap for more steps...

Step 6.1

Simplify.

Tap for more steps...

Step 6.1.1

Combine ${(3 - x)}^{\frac{3}{2}}$ and $\frac{2}{3}$ .

$(x + 4) (- \frac{{(3 - x)}^{\frac{3}{2}} \cdot 2}{3}) - (- \frac{2}{3} (- (\frac{2}{5} u^{\frac{5}{2}} + C)))$

Step 6.1.2

Move $2$ to the left of ${(3 - x)}^{\frac{3}{2}}$ .

$(x + 4) (- \frac{2 \cdot {(3 - x)}^{\frac{3}{2}}}{3}) - (- \frac{2}{3} (- (\frac{2}{5} u^{\frac{5}{2}} + C)))$

Step 6.1.3

Combine $\frac{2}{5}$ and $u^{\frac{5}{2}}$ .

$(x + 4) (- \frac{2 {(3 - x)}^{\frac{3}{2}}}{3}) - (- \frac{2}{3} (- (\frac{2 u^{\frac{5}{2}}}{5} + C)))$

Step 6.1.4

Multiply $- 1$ by $- 1$ .

$(x + 4) (- \frac{2 {(3 - x)}^{\frac{3}{2}}}{3}) - (1 (\frac{2}{3}) (\frac{2 u^{\frac{5}{2}}}{5} + C))$

Step 6.1.5

Multiply $\frac{2}{3}$ by $1$ .

$(x + 4) (- \frac{2 {(3 - x)}^{\frac{3}{2}}}{3}) - \frac{2}{3} (\frac{2 u^{\frac{5}{2}}}{5} + C)$

Step 6.2

Rewrite $(x + 4) (- \frac{2 {(3 - x)}^{\frac{3}{2}}}{3}) - \frac{2}{3} (\frac{2 u^{\frac{5}{2}}}{5} + C)$ as $- x \frac{2 {(3 - x)}^{\frac{3}{2}}}{3} + \frac{- 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{2}{3} \cdot \frac{2 u^{\frac{5}{2}}}{5} + C$ .

$- x \frac{2 {(3 - x)}^{\frac{3}{2}}}{3} + \frac{- 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{2}{3} \cdot \frac{2 u^{\frac{5}{2}}}{5} + C$

Step 6.3

Simplify.

Tap for more steps...

Step 6.3.1

Combine $\frac{2 {(3 - x)}^{\frac{3}{2}}}{3}$ and $x$ .

$- \frac{2 {(3 - x)}^{\frac{3}{2}} x}{3} + \frac{- 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{2}{3} \cdot \frac{2 u^{\frac{5}{2}}}{5} + C$

Step 6.3.2

Move the negative in front of the fraction.

$- \frac{2 {(3 - x)}^{\frac{3}{2}} x}{3} - \frac{8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{2}{3} \cdot \frac{2 u^{\frac{5}{2}}}{5} + C$

Step 6.3.3

Combine the numerators over the common denominator.

$\frac{- 2 {(3 - x)}^{\frac{3}{2}} x - 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{2}{3} \cdot \frac{2 u^{\frac{5}{2}}}{5} + C$

Step 6.3.4

Multiply $\frac{2 u^{\frac{5}{2}}}{5}$ by $\frac{2}{3}$ .

$\frac{- 2 {(3 - x)}^{\frac{3}{2}} x - 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{2 u^{\frac{5}{2}} \cdot 2}{5 \cdot 3} + C$

Step 6.3.5

Multiply $2$ by $2$ .

$\frac{- 2 {(3 - x)}^{\frac{3}{2}} x - 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{4 u^{\frac{5}{2}}}{5 \cdot 3} + C$

Step 6.3.6

Multiply $5$ by $3$ .

$\frac{- 2 {(3 - x)}^{\frac{3}{2}} x - 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{4 u^{\frac{5}{2}}}{15} + C$

Step 7

Replace all occurrences of $u$ with $3 - x$ .

$\frac{- 2 {(3 - x)}^{\frac{3}{2}} x - 8 {(3 - x)}^{\frac{3}{2}}}{3} - \frac{4 {(3 - x)}^{\frac{5}{2}}}{15} + C$

Step 8

Reorder terms.

$\frac{1}{3} (- 2 {(3 - x)}^{\frac{3}{2}} x - 8 {(3 - x)}^{\frac{3}{2}}) - \frac{4}{15} {(3 - x)}^{\frac{5}{2}} + C$