Calculus Examples

$\int \sqrt{x^{2} - 1} d x$

Step 1

Let $x = \sec (t)$ , where $- \frac{π}{2} \leq t \leq \frac{π}{2}$ . Then $d x = \sec (t) \tan (t) d t$ . Note that since $- \frac{π}{2} \leq t \leq \frac{π}{2}$ , $\sec (t) \tan (t)$ is positive.

$\int \sqrt{\sec^{2} (t) - 1} (\sec (t) \tan (t)) d t$

Step 2

Simplify terms.

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Step 2.1

Simplify $\sqrt{\sec^{2} (t) - 1}$ .

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Step 2.1.1

Apply pythagorean identity.

$\int \sqrt{\tan^{2} (t)} (\sec (t) \tan (t)) d t$

Step 2.1.2

Pull terms out from under the radical, assuming positive real numbers.

$\int \tan (t) (\sec (t) \tan (t)) d t$

Step 2.2

Simplify.

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Step 2.2.1

Raise $\tan (t)$ to the power of $1$ .

$\int \tan^{1} (t) \tan (t) \sec (t) d t$

Step 2.2.2

Raise $\tan (t)$ to the power of $1$ .

$\int \tan^{1} (t) \tan^{1} (t) \sec (t) d t$

Step 2.2.3

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$\int {\tan (t)}^{1 + 1} \sec (t) d t$

Step 2.2.4

Add $1$ and $1$ .

$\int \tan^{2} (t) \sec (t) d t$

Step 3

Raise $\sec (t)$ to the power of $1$ .

$\int \tan^{2} (t) \sec^{1} (t) d t$

Step 4

Using the Pythagorean Identity, rewrite $\tan^{2} (t)$ as $- 1 + \sec^{2} (t)$ .

$\int (- 1 + \sec^{2} (t)) \sec^{1} (t) d t$

Step 5

Simplify terms.

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Step 5.1

Apply the distributive property.

$\int - 1 \sec^{1} (t) + \sec^{2} (t) \sec^{1} (t) d t$

Step 5.2

Simplify each term.

$\int - \sec (t) + \sec^{3} (t) d t$

Step 6

Split the single integral into multiple integrals.

$\int - \sec (t) d t + \int \sec^{3} (t) d t$

Step 7

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

$- \int \sec (t) d t + \int \sec^{3} (t) d t$

Step 8

The integral of $\sec (t)$ with respect to $t$ is $\ln (| \sec (t) + \tan (t) |)$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \int \sec^{3} (t) d t$

Step 9

Factor $\sec (t)$ out of $\sec^{3} (t)$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \int \sec (t) \sec^{2} (t) d t$

Step 10

Integrate by parts using the formula $\int u d v = u v - \int v d u$ , where $u = \sec (t)$ and $d v = \sec^{2} (t)$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \tan (t) (\sec (t) \tan (t)) d t$

Step 11

Raise $\tan (t)$ to the power of $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \tan^{1} (t) \tan (t) \sec (t) d t$

Step 12

Raise $\tan (t)$ to the power of $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \tan^{1} (t) \tan^{1} (t) \sec (t) d t$

Step 13

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int {\tan (t)}^{1 + 1} \sec (t) d t$

Step 14

Simplify the expression.

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Step 14.1

Add $1$ and $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \tan^{2} (t) \sec (t) d t$

Step 14.2

Reorder $\tan^{2} (t)$ and $\sec (t)$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \sec (t) \tan^{2} (t) d t$

Step 15

Using the Pythagorean Identity, rewrite $\tan^{2} (t)$ as $- 1 + \sec^{2} (t)$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \sec (t) (- 1 + \sec^{2} (t)) d t$

Step 16

Simplify by multiplying through.

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Step 16.1

Rewrite the exponentiation as a product.

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \sec (t) (- 1 + \sec (t) \sec (t)) d t$

Step 16.2

Apply the distributive property.

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int \sec (t) \cdot - 1 + \sec (t) (\sec (t) \sec (t)) d t$

Step 16.3

Reorder $\sec (t)$ and $- 1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \cdot \sec (t) + \sec (t) (\sec (t) \sec (t)) d t$

Step 17

Raise $\sec (t)$ to the power of $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \sec (t) + \sec^{1} (t) \sec (t) \sec (t) d t$

Step 18

Raise $\sec (t)$ to the power of $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \sec (t) + \sec^{1} (t) \sec^{1} (t) \sec (t) d t$

Step 19

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \sec (t) + {\sec (t)}^{1 + 1} \sec (t) d t$

Step 20

Add $1$ and $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \sec (t) + \sec^{2} (t) \sec (t) d t$

Step 21

Raise $\sec (t)$ to the power of $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \sec (t) + \sec^{2} (t) \sec^{1} (t) d t$

Step 22

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \sec (t) + {\sec (t)}^{2 + 1} d t$

Step 23

Add $2$ and $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - \int - 1 \sec (t) + \sec^{3} (t) d t$

Step 24

Split the single integral into multiple integrals.

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - (\int - 1 \sec (t) d t + \int \sec^{3} (t) d t)$

Step 25

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

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - (- \int \sec (t) d t + \int \sec^{3} (t) d t)$

Step 26

The integral of $\sec (t)$ with respect to $t$ is $\ln (| \sec (t) + \tan (t) |)$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - (- (\ln (| \sec (t) + \tan (t) |) + C) + \int \sec^{3} (t) d t)$

Step 27

Simplify by multiplying through.

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Step 27.1

Apply the distributive property.

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) - - (\ln (| \sec (t) + \tan (t) |) + C) - \int \sec^{3} (t) d t$

Step 27.2

Multiply $- 1$ by $- 1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \sec (t) \tan (t) + 1 (\ln (| \sec (t) + \tan (t) |) + C) - \int \sec^{3} (t) d t$

Step 28

Solving for $\int \sec^{3} (t) d t$ , we find that $\int \sec^{3} (t) d t$ = $\frac{\sec (t) \tan (t) + 1 (\ln (| \sec (t) + \tan (t) |) + C)}{2}$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \frac{\sec (t) \tan (t) + 1 (\ln (| \sec (t) + \tan (t) |) + C)}{2} + C$

Step 29

Multiply $\ln (| \sec (t) + \tan (t) |) + C$ by $1$ .

$- (\ln (| \sec (t) + \tan (t) |) + C) + \frac{\sec (t) \tan (t) + \ln (| \sec (t) + \tan (t) |) + C}{2} + C$

Step 30

Simplify.

$- \ln (| \sec (t) + \tan (t) |) + \frac{1}{2} (\sec (t) \tan (t) + \ln (| \sec (t) + \tan (t) |)) + C$

Step 31

Replace all occurrences of $t$ with $arcsec (x)$ .

$- \ln (| \sec (arcsec (x)) + \tan (arcsec (x)) |) + \frac{1}{2} (\sec (arcsec (x)) \tan (arcsec (x)) + \ln (| \sec (arcsec (x)) + \tan (arcsec (x)) |)) + C$