Calculus Examples

$- 9 \sin (3 x) = 0$

Step 1

Divide each term in $- 9 \sin (3 x) = 0$ by $- 9$ and simplify.

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Step 1.1

Divide each term in $- 9 \sin (3 x) = 0$ by $- 9$ .

$\frac{- 9 \sin (3 x)}{- 9} = \frac{0}{- 9}$

Step 1.2

Simplify the left side.

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Step 1.2.1

Cancel the common factor of $- 9$ .

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Step 1.2.1.1

Cancel the common factor.

$\frac{- 9 \sin (3 x)}{- 9} = \frac{0}{- 9}$

Step 1.2.1.2

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

$\sin (3 x) = \frac{0}{- 9}$

Step 1.3

Simplify the right side.

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Step 1.3.1

Divide $0$ by $- 9$ .

$\sin (3 x) = 0$

Step 2

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

$3 x = \arcsin (0)$

Step 3

Simplify the right side.

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Step 3.1

The exact value of $\arcsin (0)$ is $0$ .

$3 x = 0$

Step 4

Divide each term in $3 x = 0$ by $3$ and simplify.

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Step 4.1

Divide each term in $3 x = 0$ by $3$ .

$\frac{3 x}{3} = \frac{0}{3}$

Step 4.2

Simplify the left side.

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Step 4.2.1

Cancel the common factor of $3$ .

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Step 4.2.1.1

Cancel the common factor.

$\frac{3 x}{3} = \frac{0}{3}$

Step 4.2.1.2

Divide $x$ by $1$ .

$x = \frac{0}{3}$

Step 4.3

Simplify the right side.

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Step 4.3.1

Divide $0$ by $3$ .

$x = 0$

Step 5

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

$3 x = π - 0$

Step 6

Solve for $x$ .

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Step 6.1

Simplify.

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Step 6.1.1

Multiply $- 1$ by $0$ .

$3 x = π + 0$

Step 6.1.2

Add $π$ and $0$ .

$3 x = π$

Step 6.2

Divide each term in $3 x = π$ by $3$ and simplify.

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Step 6.2.1

Divide each term in $3 x = π$ by $3$ .

$\frac{3 x}{3} = \frac{π}{3}$

Step 6.2.2

Simplify the left side.

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Step 6.2.2.1

Cancel the common factor of $3$ .

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Step 6.2.2.1.1

Cancel the common factor.

$\frac{3 x}{3} = \frac{π}{3}$

Step 6.2.2.1.2

Divide $x$ by $1$ .

$x = \frac{π}{3}$

Step 7

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

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Step 7.1

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

$\frac{2 π}{| b |}$

Step 7.2

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

$\frac{2 π}{| 3 |}$

Step 7.3

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

$\frac{2 π}{3}$

Step 8

The period of the $\sin (3 x)$ function is $\frac{2 π}{3}$ so values will repeat every $\frac{2 π}{3}$ radians in both directions.

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

Step 9

Consolidate the answers.

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