Trigonometry Examples

$\tan (x) = 2 \sin (x)$

Step 1

Divide each term in $\tan (x) = 2 \sin (x)$ by $\tan (x)$ and simplify.

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Step 1.1

Divide each term in $\tan (x) = 2 \sin (x)$ by $\tan (x)$ .

$\frac{\tan (x)}{\tan (x)} = \frac{2 \sin (x)}{\tan (x)}$

Step 1.2

Simplify the left side.

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Step 1.2.1

Cancel the common factor of $\tan (x)$ .

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Step 1.2.1.1

Cancel the common factor.

$\frac{\tan (x)}{\tan (x)} = \frac{2 \sin (x)}{\tan (x)}$

Step 1.2.1.2

Rewrite the expression.

$1 = \frac{2 \sin (x)}{\tan (x)}$

Step 1.3

Simplify the right side.

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Step 1.3.1

Separate fractions.

$1 = \frac{2}{1} \cdot \frac{\sin (x)}{\tan (x)}$

Step 1.3.2

Rewrite $\tan (x)$ in terms of sines and cosines.

$1 = \frac{2}{1} \cdot \frac{\sin (x)}{\frac{\sin (x)}{\cos (x)}}$

Step 1.3.3

Multiply by the reciprocal of the fraction to divide by $\frac{\sin (x)}{\cos (x)}$ .

$1 = \frac{2}{1} (\sin (x) \frac{\cos (x)}{\sin (x)})$

Step 1.3.4

Write $\sin (x)$ as a fraction with denominator $1$ .

$1 = \frac{2}{1} (\frac{\sin (x)}{1} \cdot \frac{\cos (x)}{\sin (x)})$

Step 1.3.5

Cancel the common factor of $\sin (x)$ .

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Step 1.3.5.1

Cancel the common factor.

$1 = \frac{2}{1} (\frac{\sin (x)}{1} \cdot \frac{\cos (x)}{\sin (x)})$

Step 1.3.5.2

Rewrite the expression.

$1 = \frac{2}{1} \cos (x)$

Step 1.3.6

Divide $2$ by $1$ .

$1 = 2 \cos (x)$

Step 2

Rewrite the equation as $2 \cos (x) = 1$ .

$2 \cos (x) = 1$

Step 3

Divide each term in $2 \cos (x) = 1$ by $2$ and simplify.

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Step 3.1

Divide each term in $2 \cos (x) = 1$ by $2$ .

$\frac{2 \cos (x)}{2} = \frac{1}{2}$

Step 3.2

Simplify the left side.

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Step 3.2.1

Cancel the common factor of $2$ .

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Step 3.2.1.1

Cancel the common factor.

$\frac{2 \cos (x)}{2} = \frac{1}{2}$

Step 3.2.1.2

Divide $\cos (x)$ by $1$ .

$\cos (x) = \frac{1}{2}$

Step 4

Take the inverse cosine of both sides of the equation to extract $x$ from inside the cosine.

$x = \arccos (\frac{1}{2})$

Step 5

Simplify the right side.

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Step 5.1

The exact value of $\arccos (\frac{1}{2})$ is $\frac{π}{3}$ .

$x = \frac{π}{3}$

Step 6

The cosine function is positive in the first and fourth quadrants. To find the second solution, subtract the reference angle from $2 π$ to find the solution in the fourth quadrant.

$x = 2 π - \frac{π}{3}$

Step 7

Simplify $2 π - \frac{π}{3}$ .

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Step 7.1

To write $2 π$ as a fraction with a common denominator, multiply by $\frac{3}{3}$ .

$x = 2 π \cdot \frac{3}{3} - \frac{π}{3}$

Step 7.2

Combine fractions.

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Step 7.2.1

Combine $2 π$ and $\frac{3}{3}$ .

$x = \frac{2 π \cdot 3}{3} - \frac{π}{3}$

Step 7.2.2

Combine the numerators over the common denominator.

$x = \frac{2 π \cdot 3 - π}{3}$

Step 7.3

Simplify the numerator.

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Step 7.3.1

Multiply $3$ by $2$ .

$x = \frac{6 π - π}{3}$

Step 7.3.2

Subtract $π$ from $6 π$ .

$x = \frac{5 π}{3}$

Step 8

Find the period of $\cos (x)$ .

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Step 8.1

The period of the function can be calculated using $\frac{2 π}{| b |}$ .

$\frac{2 π}{| b |}$

Step 8.2

Replace $b$ with $1$ in the formula for period.

$\frac{2 π}{| 1 |}$

Step 8.3

The absolute value is the distance between a number and zero. The distance between $0$ and $1$ is $1$ .

$\frac{2 π}{1}$

Step 8.4

Divide $2 π$ by $1$ .

$2 π$

Step 9

The period of the $\cos (x)$ function is $2 π$ so values will repeat every $2 π$ radians in both directions.

$x = \frac{π}{3} + 2 π n, \frac{5 π}{3} + 2 π n$ , for any integer $n$