Precalculus Examples

${(\frac{1}{3} x + y^{2})}^{3}$

Step 1

Pascal's Triangle can be displayed as such:

$1$

$1 - 1$

$1 - 2 - 1$

$1 - 3 - 3 - 1$

The triangle can be used to calculate the coefficients of the expansion of ${(a + b)}^{n}$ by taking the exponent $n$ and adding $1$ . The coefficients will correspond with line $n + 1$ of the triangle. For ${(\frac{1}{3} x + y^{2})}^{3}$ , $n = 3$ so the coefficients of the expansion will correspond with line $4$ .

Step 2

The expansion follows the rule ${(a + b)}^{n} = c_{0} a^{n} b^{0} + c_{1} a^{n - 1} b^{1} + c_{n - 1} a^{1} b^{n - 1} + c_{n} a^{0} b^{n}$ . The values of the coefficients, from the triangle, are $1 - 3 - 3 - 1$ .

$1 a^{3} b^{0} + 3 a^{2} b + 3 a b^{2} + 1 a^{0} b^{3}$

Step 3

Substitute the actual values of $a$ $\frac{1}{3} x$ and $b$ $y^{2}$ into the expression.

$1 {(\frac{1}{3} x)}^{3} {(y^{2})}^{0} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4

Simplify each term.

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Step 4.1

Multiply ${(\frac{1}{3} x)}^{3}$ by $1$ .

${(\frac{1}{3} x)}^{3} {(y^{2})}^{0} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.2

Combine $\frac{1}{3}$ and $x$ .

${(\frac{x}{3})}^{3} {(y^{2})}^{0} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.3

Apply the product rule to $\frac{x}{3}$ .

$\frac{x^{3}}{3^{3}} {(y^{2})}^{0} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.4

Raise $3$ to the power of $3$ .

$\frac{x^{3}}{27} {(y^{2})}^{0} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.5

Multiply the exponents in ${(y^{2})}^{0}$ .

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Step 4.5.1

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

$\frac{x^{3}}{27} y^{2 \cdot 0} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.5.2

Multiply $2$ by $0$ .

$\frac{x^{3}}{27} y^{0} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.6

Anything raised to $0$ is $1$ .

$\frac{x^{3}}{27} \cdot 1 + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.7

Multiply $\frac{x^{3}}{27}$ by $1$ .

$\frac{x^{3}}{27} + 3 {(\frac{1}{3} x)}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.8

Combine $\frac{1}{3}$ and $x$ .

$\frac{x^{3}}{27} + 3 {(\frac{x}{3})}^{2} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.9

Apply the product rule to $\frac{x}{3}$ .

$\frac{x^{3}}{27} + 3 \frac{x^{2}}{3^{2}} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.10

Raise $3$ to the power of $2$ .

$\frac{x^{3}}{27} + 3 \frac{x^{2}}{9} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.11

Cancel the common factor of $3$ .

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Step 4.11.1

Factor $3$ out of $9$ .

$\frac{x^{3}}{27} + 3 \frac{x^{2}}{3 (3)} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.11.2

Cancel the common factor.

$\frac{x^{3}}{27} + 3 \frac{x^{2}}{3 \cdot 3} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.11.3

Rewrite the expression.

$\frac{x^{3}}{27} + \frac{x^{2}}{3} {(y^{2})}^{1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.12

Multiply the exponents in ${(y^{2})}^{1}$ .

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Step 4.12.1

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

$\frac{x^{3}}{27} + \frac{x^{2}}{3} y^{2 \cdot 1} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.12.2

Multiply $2$ by $1$ .

$\frac{x^{3}}{27} + \frac{x^{2}}{3} y^{2} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.13

Combine $\frac{x^{2}}{3}$ and $y^{2}$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + 3 {(\frac{1}{3} x)}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.14

Combine $\frac{1}{3}$ and $x$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + 3 {(\frac{x}{3})}^{1} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.15

Simplify.

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + 3 \frac{x}{3} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.16

Cancel the common factor of $3$ .

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Step 4.16.1

Cancel the common factor.

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + 3 \frac{x}{3} {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.16.2

Rewrite the expression.

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x {(y^{2})}^{2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.17

Multiply the exponents in ${(y^{2})}^{2}$ .

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Step 4.17.1

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

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{2 \cdot 2} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.17.2

Multiply $2$ by $2$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + 1 {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.18

Multiply ${(\frac{1}{3} x)}^{0}$ by $1$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + {(\frac{1}{3} x)}^{0} {(y^{2})}^{3}$

Step 4.19

Combine $\frac{1}{3}$ and $x$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + {(\frac{x}{3})}^{0} {(y^{2})}^{3}$

Step 4.20

Apply the product rule to $\frac{x}{3}$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + \frac{x^{0}}{3^{0}} {(y^{2})}^{3}$

Step 4.21

Anything raised to $0$ is $1$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + \frac{1}{3^{0}} {(y^{2})}^{3}$

Step 4.22

Anything raised to $0$ is $1$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + \frac{1}{1} {(y^{2})}^{3}$

Step 4.23

Divide $1$ by $1$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + 1 {(y^{2})}^{3}$

Step 4.24

Multiply ${(y^{2})}^{3}$ by $1$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + {(y^{2})}^{3}$

Step 4.25

Multiply the exponents in ${(y^{2})}^{3}$ .

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Step 4.25.1

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

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + y^{2 \cdot 3}$

Step 4.25.2

Multiply $2$ by $3$ .

$\frac{x^{3}}{27} + \frac{x^{2} y^{2}}{3} + x y^{4} + y^{6}$