Precalculus Examples

$\frac{x^{3}}{\sqrt[3]{1 - x^{3}}}$

Step 1

Set the denominator in $\frac{x^{3}}{\sqrt[3]{1 - x^{3}}}$ equal to $0$ to find where the expression is undefined.

$\sqrt[3]{1 - x^{3}} = 0$

Step 2

Solve for $x$ .

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Step 2.1

To remove the radical on the left side of the equation, cube both sides of the equation.

${\sqrt[3]{1 - x^{3}}}^{3} = 0^{3}$

Step 2.2

Simplify each side of the equation.

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Step 2.2.1

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

${({(1 - x^{3})}^{\frac{1}{3}})}^{3} = 0^{3}$

Step 2.2.2

Simplify the left side.

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Step 2.2.2.1

Simplify ${({(1 - x^{3})}^{\frac{1}{3}})}^{3}$ .

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Step 2.2.2.1.1

Multiply the exponents in ${({(1 - x^{3})}^{\frac{1}{3}})}^{3}$ .

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Step 2.2.2.1.1.1

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

${(1 - x^{3})}^{\frac{1}{3} \cdot 3} = 0^{3}$

Step 2.2.2.1.1.2

Cancel the common factor of $3$ .

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Step 2.2.2.1.1.2.1

Cancel the common factor.

${(1 - x^{3})}^{\frac{1}{3} \cdot 3} = 0^{3}$

Step 2.2.2.1.1.2.2

Rewrite the expression.

${(1 - x^{3})}^{1} = 0^{3}$

Step 2.2.2.1.2

Simplify.

$1 - x^{3} = 0^{3}$

Step 2.2.3

Simplify the right side.

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Step 2.2.3.1

Raising $0$ to any positive power yields $0$ .

$1 - x^{3} = 0$

Step 2.3

Solve for $x$ .

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Step 2.3.1

Subtract $1$ from both sides of the equation.

$- x^{3} = - 1$

Step 2.3.2

Add $1$ to both sides of the equation.

$- x^{3} + 1 = 0$

Step 2.3.3

Factor the left side of the equation.

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Step 2.3.3.1

Factor $- 1$ out of $- x^{3} + 1$ .

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Step 2.3.3.1.1

Factor $- 1$ out of $- x^{3}$ .

$- (x^{3}) + 1 = 0$

Step 2.3.3.1.2

Rewrite $1$ as $- 1 (- 1)$ .

$- (x^{3}) - 1 \cdot - 1 = 0$

Step 2.3.3.1.3

Factor $- 1$ out of $- (x^{3}) - 1 (- 1)$ .

$- (x^{3} - 1) = 0$

Step 2.3.3.2

Rewrite $1$ as $1^{3}$ .

$- (x^{3} - 1^{3}) = 0$

Step 2.3.3.3

Since both terms are perfect cubes, factor using the difference of cubes formula, $a^{3} - b^{3} = (a - b) (a^{2} + a b + b^{2})$ where $a = x$ and $b = 1$ .

$- ((x - 1) (x^{2} + x \cdot 1 + 1^{2})) = 0$

Step 2.3.3.4

Factor.

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Step 2.3.3.4.1

Simplify.

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Step 2.3.3.4.1.1

Multiply $x$ by $1$ .

$- ((x - 1) (x^{2} + x + 1^{2})) = 0$

Step 2.3.3.4.1.2

One to any power is one.

$- ((x - 1) (x^{2} + x + 1)) = 0$

Step 2.3.3.4.2

Remove unnecessary parentheses.

$- (x - 1) (x^{2} + x + 1) = 0$

Step 2.3.4

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$x - 1 = 0$

$x^{2} + x + 1 = 0$

Step 2.3.5

Set $x - 1$ equal to $0$ and solve for $x$ .

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Step 2.3.5.1

Set $x - 1$ equal to $0$ .

$x - 1 = 0$

Step 2.3.5.2

Add $1$ to both sides of the equation.

$x = 1$

Step 2.3.6

Set $x^{2} + x + 1$ equal to $0$ and solve for $x$ .

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Step 2.3.6.1

Set $x^{2} + x + 1$ equal to $0$ .

$x^{2} + x + 1 = 0$

Step 2.3.6.2

Solve $x^{2} + x + 1 = 0$ for $x$ .

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Step 2.3.6.2.1

Use the quadratic formula to find the solutions.

$\frac{- b \pm \sqrt{b^{2} - 4 (a c)}}{2 a}$

Step 2.3.6.2.2

Substitute the values $a = 1$ , $b = 1$ , and $c = 1$ into the quadratic formula and solve for $x$ .

$\frac{- 1 \pm \sqrt{1^{2} - 4 \cdot (1 \cdot 1)}}{2 \cdot 1}$

Step 2.3.6.2.3

Simplify.

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Step 2.3.6.2.3.1

Simplify the numerator.

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Step 2.3.6.2.3.1.1

One to any power is one.

$x = \frac{- 1 \pm \sqrt{1 - 4 \cdot 1 \cdot 1}}{2 \cdot 1}$

Step 2.3.6.2.3.1.2

Multiply $- 4 \cdot 1 \cdot 1$ .

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Step 2.3.6.2.3.1.2.1

Multiply $- 4$ by $1$ .

$x = \frac{- 1 \pm \sqrt{1 - 4 \cdot 1}}{2 \cdot 1}$

Step 2.3.6.2.3.1.2.2

Multiply $- 4$ by $1$ .

$x = \frac{- 1 \pm \sqrt{1 - 4}}{2 \cdot 1}$

Step 2.3.6.2.3.1.3

Subtract $4$ from $1$ .

$x = \frac{- 1 \pm \sqrt{- 3}}{2 \cdot 1}$

Step 2.3.6.2.3.1.4

Rewrite $- 3$ as $- 1 (3)$ .

$x = \frac{- 1 \pm \sqrt{- 1 \cdot 3}}{2 \cdot 1}$

Step 2.3.6.2.3.1.5

Rewrite $\sqrt{- 1 (3)}$ as $\sqrt{- 1} \cdot \sqrt{3}$ .

$x = \frac{- 1 \pm \sqrt{- 1} \cdot \sqrt{3}}{2 \cdot 1}$

Step 2.3.6.2.3.1.6

Rewrite $\sqrt{- 1}$ as $i$ .

$x = \frac{- 1 \pm i \sqrt{3}}{2 \cdot 1}$

Step 2.3.6.2.3.2

Multiply $2$ by $1$ .

$x = \frac{- 1 \pm i \sqrt{3}}{2}$

Step 2.3.6.2.4

Simplify the expression to solve for the $+$ portion of the $\pm$ .

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Step 2.3.6.2.4.1

Simplify the numerator.

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Step 2.3.6.2.4.1.1

One to any power is one.

$x = \frac{- 1 \pm \sqrt{1 - 4 \cdot 1 \cdot 1}}{2 \cdot 1}$

Step 2.3.6.2.4.1.2

Multiply $- 4 \cdot 1 \cdot 1$ .

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Step 2.3.6.2.4.1.2.1

Multiply $- 4$ by $1$ .

$x = \frac{- 1 \pm \sqrt{1 - 4 \cdot 1}}{2 \cdot 1}$

Step 2.3.6.2.4.1.2.2

Multiply $- 4$ by $1$ .

$x = \frac{- 1 \pm \sqrt{1 - 4}}{2 \cdot 1}$

Step 2.3.6.2.4.1.3

Subtract $4$ from $1$ .

$x = \frac{- 1 \pm \sqrt{- 3}}{2 \cdot 1}$

Step 2.3.6.2.4.1.4

Rewrite $- 3$ as $- 1 (3)$ .

$x = \frac{- 1 \pm \sqrt{- 1 \cdot 3}}{2 \cdot 1}$

Step 2.3.6.2.4.1.5

Rewrite $\sqrt{- 1 (3)}$ as $\sqrt{- 1} \cdot \sqrt{3}$ .

$x = \frac{- 1 \pm \sqrt{- 1} \cdot \sqrt{3}}{2 \cdot 1}$

Step 2.3.6.2.4.1.6

Rewrite $\sqrt{- 1}$ as $i$ .

$x = \frac{- 1 \pm i \sqrt{3}}{2 \cdot 1}$

Step 2.3.6.2.4.2

Multiply $2$ by $1$ .

$x = \frac{- 1 \pm i \sqrt{3}}{2}$

Step 2.3.6.2.4.3

Change the $\pm$ to $+$ .

$x = \frac{- 1 + i \sqrt{3}}{2}$

Step 2.3.6.2.4.4

Rewrite $- 1$ as $- 1 (1)$ .

$x = \frac{- 1 \cdot 1 + i \sqrt{3}}{2}$

Step 2.3.6.2.4.5

Factor $- 1$ out of $i \sqrt{3}$ .

$x = \frac{- 1 \cdot 1 - (- i \sqrt{3})}{2}$

Step 2.3.6.2.4.6

Factor $- 1$ out of $- 1 (1) - (- i \sqrt{3})$ .

$x = \frac{- 1 (1 - i \sqrt{3})}{2}$

Step 2.3.6.2.4.7

Move the negative in front of the fraction.

$x = - \frac{1 - i \sqrt{3}}{2}$

Step 2.3.6.2.5

Simplify the expression to solve for the $-$ portion of the $\pm$ .

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Step 2.3.6.2.5.1

Simplify the numerator.

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Step 2.3.6.2.5.1.1

One to any power is one.

$x = \frac{- 1 \pm \sqrt{1 - 4 \cdot 1 \cdot 1}}{2 \cdot 1}$

Step 2.3.6.2.5.1.2

Multiply $- 4 \cdot 1 \cdot 1$ .

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Step 2.3.6.2.5.1.2.1

Multiply $- 4$ by $1$ .

$x = \frac{- 1 \pm \sqrt{1 - 4 \cdot 1}}{2 \cdot 1}$

Step 2.3.6.2.5.1.2.2

Multiply $- 4$ by $1$ .

$x = \frac{- 1 \pm \sqrt{1 - 4}}{2 \cdot 1}$

Step 2.3.6.2.5.1.3

Subtract $4$ from $1$ .

$x = \frac{- 1 \pm \sqrt{- 3}}{2 \cdot 1}$

Step 2.3.6.2.5.1.4

Rewrite $- 3$ as $- 1 (3)$ .

$x = \frac{- 1 \pm \sqrt{- 1 \cdot 3}}{2 \cdot 1}$

Step 2.3.6.2.5.1.5

Rewrite $\sqrt{- 1 (3)}$ as $\sqrt{- 1} \cdot \sqrt{3}$ .

$x = \frac{- 1 \pm \sqrt{- 1} \cdot \sqrt{3}}{2 \cdot 1}$

Step 2.3.6.2.5.1.6

Rewrite $\sqrt{- 1}$ as $i$ .

$x = \frac{- 1 \pm i \sqrt{3}}{2 \cdot 1}$

Step 2.3.6.2.5.2

Multiply $2$ by $1$ .

$x = \frac{- 1 \pm i \sqrt{3}}{2}$

Step 2.3.6.2.5.3

Change the $\pm$ to $-$ .

$x = \frac{- 1 - i \sqrt{3}}{2}$

Step 2.3.6.2.5.4

Rewrite $- 1$ as $- 1 (1)$ .

$x = \frac{- 1 \cdot 1 - i \sqrt{3}}{2}$

Step 2.3.6.2.5.5

Factor $- 1$ out of $- i \sqrt{3}$ .

$x = \frac{- 1 \cdot 1 - (i \sqrt{3})}{2}$

Step 2.3.6.2.5.6

Factor $- 1$ out of $- 1 (1) - (i \sqrt{3})$ .

$x = \frac{- 1 (1 + i \sqrt{3})}{2}$

Step 2.3.6.2.5.7

Move the negative in front of the fraction.

$x = - \frac{1 + i \sqrt{3}}{2}$

Step 2.3.6.2.6

The final answer is the combination of both solutions.

$x = - \frac{1 - i \sqrt{3}}{2}, - \frac{1 + i \sqrt{3}}{2}$

Step 2.3.7

The final solution is all the values that make $- (x - 1) (x^{2} + x + 1) = 0$ true.

$x = 1, - \frac{1 - i \sqrt{3}}{2}, - \frac{1 + i \sqrt{3}}{2}$

Step 3

The domain is all values of $x$ that make the expression defined.

Interval Notation:

$(- \infty, 1) \cup (1, \infty)$

Set-Builder Notation:

${x | x \neq 1}$

Step 4