Trigonometry Examples

$\sqrt{3} \cot (3 x) - 1 = 0$

Step 1

Add $1$ to both sides of the equation.

$\sqrt{3} \cot (3 x) = 1$

Step 2

Divide each term in $\sqrt{3} \cot (3 x) = 1$ by $\sqrt{3}$ and simplify.

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Step 2.1

Divide each term in $\sqrt{3} \cot (3 x) = 1$ by $\sqrt{3}$ .

$\frac{\sqrt{3} \cot (3 x)}{\sqrt{3}} = \frac{1}{\sqrt{3}}$

Step 2.2

Simplify the left side.

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Step 2.2.1

Cancel the common factor of $\sqrt{3}$ .

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Step 2.2.1.1

Cancel the common factor.

$\frac{\sqrt{3} \cot (3 x)}{\sqrt{3}} = \frac{1}{\sqrt{3}}$

Step 2.2.1.2

Divide $\cot (3 x)$ by $1$ .

$\cot (3 x) = \frac{1}{\sqrt{3}}$

Step 2.3

Simplify the right side.

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Step 2.3.1

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

$\cot (3 x) = \frac{1}{\sqrt{3}} \cdot \frac{\sqrt{3}}{\sqrt{3}}$

Step 2.3.2

Combine and simplify the denominator.

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Step 2.3.2.1

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

$\cot (3 x) = \frac{\sqrt{3}}{\sqrt{3} \sqrt{3}}$

Step 2.3.2.2

Raise $\sqrt{3}$ to the power of $1$ .

$\cot (3 x) = \frac{\sqrt{3}}{{\sqrt{3}}^{1} \sqrt{3}}$

Step 2.3.2.3

Raise $\sqrt{3}$ to the power of $1$ .

$\cot (3 x) = \frac{\sqrt{3}}{{\sqrt{3}}^{1} {\sqrt{3}}^{1}}$

Step 2.3.2.4

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

$\cot (3 x) = \frac{\sqrt{3}}{{\sqrt{3}}^{1 + 1}}$

Step 2.3.2.5

Add $1$ and $1$ .

$\cot (3 x) = \frac{\sqrt{3}}{{\sqrt{3}}^{2}}$

Step 2.3.2.6

Rewrite ${\sqrt{3}}^{2}$ as $3$ .

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Step 2.3.2.6.1

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{3}$ as $3^{\frac{1}{2}}$ .

$\cot (3 x) = \frac{\sqrt{3}}{{(3^{\frac{1}{2}})}^{2}}$

Step 2.3.2.6.2

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$\cot (3 x) = \frac{\sqrt{3}}{3^{\frac{1}{2} \cdot 2}}$

Step 2.3.2.6.3

Combine $\frac{1}{2}$ and $2$ .

$\cot (3 x) = \frac{\sqrt{3}}{3^{\frac{2}{2}}}$

Step 2.3.2.6.4

Cancel the common factor of $2$ .

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Step 2.3.2.6.4.1

Cancel the common factor.

$\cot (3 x) = \frac{\sqrt{3}}{3^{\frac{2}{2}}}$

Step 2.3.2.6.4.2

Rewrite the expression.

$\cot (3 x) = \frac{\sqrt{3}}{3^{1}}$

Step 2.3.2.6.5

Evaluate the exponent.

$\cot (3 x) = \frac{\sqrt{3}}{3}$

Step 3

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

$3 x = arccot (\frac{\sqrt{3}}{3})$

Step 4

Simplify the right side.

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Step 4.1

The exact value of $arccot (\frac{\sqrt{3}}{3})$ is $\frac{π}{3}$ .

$3 x = \frac{π}{3}$

Step 5

Divide each term in $3 x = \frac{π}{3}$ by $3$ and simplify.

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Step 5.1

Divide each term in $3 x = \frac{π}{3}$ by $3$ .

$\frac{3 x}{3} = \frac{\frac{π}{3}}{3}$

Step 5.2

Simplify the left side.

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Step 5.2.1

Cancel the common factor of $3$ .

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Step 5.2.1.1

Cancel the common factor.

$\frac{3 x}{3} = \frac{\frac{π}{3}}{3}$

Step 5.2.1.2

Divide $x$ by $1$ .

$x = \frac{\frac{π}{3}}{3}$

Step 5.3

Simplify the right side.

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Step 5.3.1

Multiply the numerator by the reciprocal of the denominator.

$x = \frac{π}{3} \cdot \frac{1}{3}$

Step 5.3.2

Multiply $\frac{π}{3} \cdot \frac{1}{3}$ .

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Step 5.3.2.1

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

$x = \frac{π}{3 \cdot 3}$

Step 5.3.2.2

Multiply $3$ by $3$ .

$x = \frac{π}{9}$

Step 6

The cotangent function is positive in the first and third quadrants. To find the second solution, add the reference angle from $π$ to find the solution in the fourth quadrant.

$3 x = π + \frac{π}{3}$

Step 7

Solve for $x$ .

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Step 7.1

Simplify.

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Step 7.1.1

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

$3 x = π \cdot \frac{3}{3} + \frac{π}{3}$

Step 7.1.2

Combine $π$ and $\frac{3}{3}$ .

$3 x = \frac{π \cdot 3}{3} + \frac{π}{3}$

Step 7.1.3

Combine the numerators over the common denominator.

$3 x = \frac{π \cdot 3 + π}{3}$

Step 7.1.4

Add $π \cdot 3$ and $π$ .

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Step 7.1.4.1

Reorder $π$ and $3$ .

$3 x = \frac{3 \cdot π + π}{3}$

Step 7.1.4.2

Add $3 \cdot π$ and $π$ .

$3 x = \frac{4 \cdot π}{3}$

Step 7.2

Divide each term in $3 x = \frac{4 \cdot π}{3}$ by $3$ and simplify.

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Step 7.2.1

Divide each term in $3 x = \frac{4 \cdot π}{3}$ by $3$ .

$\frac{3 x}{3} = \frac{\frac{4 \cdot π}{3}}{3}$

Step 7.2.2

Simplify the left side.

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Step 7.2.2.1

Cancel the common factor of $3$ .

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Step 7.2.2.1.1

Cancel the common factor.

$\frac{3 x}{3} = \frac{\frac{4 \cdot π}{3}}{3}$

Step 7.2.2.1.2

Divide $x$ by $1$ .

$x = \frac{\frac{4 \cdot π}{3}}{3}$

Step 7.2.3

Simplify the right side.

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Step 7.2.3.1

Multiply the numerator by the reciprocal of the denominator.

$x = \frac{4 \cdot π}{3} \cdot \frac{1}{3}$

Step 7.2.3.2

Multiply $\frac{4 π}{3} \cdot \frac{1}{3}$ .

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Step 7.2.3.2.1

Multiply $\frac{4 π}{3}$ by $\frac{1}{3}$ .

$x = \frac{4 π}{3 \cdot 3}$

Step 7.2.3.2.2

Multiply $3$ by $3$ .

$x = \frac{4 π}{9}$

Step 8

Find the period of $\cot (3 x)$ .

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Step 8.1

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

$\frac{π}{| b |}$

Step 8.2

Replace $b$ with $3$ in the formula for period.

$\frac{π}{| 3 |}$

Step 8.3

The absolute value is the distance between a number and zero. The distance between $0$ and $3$ is $3$ .

$\frac{π}{3}$

Step 9

The period of the $\cot (3 x)$ function is $\frac{π}{3}$ so values will repeat every $\frac{π}{3}$ radians in both directions.

$x = \frac{π}{9} + \frac{π n}{3}, \frac{4 π}{9} + \frac{π n}{3}$ , for any integer $n$

Step 10

Consolidate the answers.

$x = \frac{π}{9} + \frac{π n}{3}$ , for any integer $n$