Finite Math Examples

$(z - 4 (\cos (\frac{π}{5}) + i \sin (\frac{π}{5}))) (z - 4 (\cos (\frac{π}{5}) + i \sin (\frac{π}{5})))$

Step 1

Simplify terms.

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Step 1.1

Apply the distributive property.

$(z - 4 \cos (\frac{π}{5}) - 4 i \sin (\frac{π}{5})) (z - 4 (\cos (\frac{π}{5}) + i \sin (\frac{π}{5})))$

Step 1.2

Apply the distributive property.

$(z - 4 \cos (\frac{π}{5}) - 4 i \sin (\frac{π}{5})) (z - 4 \cos (\frac{π}{5}) - 4 i \sin (\frac{π}{5}))$

Step 2

Expand $(z - 4 \cos (\frac{π}{5}) - 4 i \sin (\frac{π}{5})) (z - 4 \cos (\frac{π}{5}) - 4 i \sin (\frac{π}{5}))$ by multiplying each term in the first expression by each term in the second expression.

$z \cdot z + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z - 4 \cos (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 \cos (\frac{π}{5}) (- 4 i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3

Simplify terms.

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Step 3.1

Simplify each term.

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Step 3.1.1

Multiply $z$ by $z$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z - 4 \cos (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 \cos (\frac{π}{5}) (- 4 i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.2

Multiply $- 4 \cos (\frac{π}{5}) (- 4 \cos (\frac{π}{5}))$ .

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Step 3.1.2.1

Multiply $- 4$ by $- 4$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos (\frac{π}{5}) \cos (\frac{π}{5}) - 4 \cos (\frac{π}{5}) (- 4 i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.2.2

Raise $\cos (\frac{π}{5})$ to the power of $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 (\cos^{1} (\frac{π}{5}) \cos (\frac{π}{5})) - 4 \cos (\frac{π}{5}) (- 4 i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.2.3

Raise $\cos (\frac{π}{5})$ to the power of $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 (\cos^{1} (\frac{π}{5}) \cos^{1} (\frac{π}{5})) - 4 \cos (\frac{π}{5}) (- 4 i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.2.4

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

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 {\cos (\frac{π}{5})}^{1 + 1} - 4 \cos (\frac{π}{5}) (- 4 i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.2.5

Add $1$ and $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) - 4 \cos (\frac{π}{5}) (- 4 i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.3

Multiply $- 4$ by $- 4$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) (i \sin (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) z - 4 i \sin (\frac{π}{5}) (- 4 \cos (\frac{π}{5})) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.4

Multiply $- 4$ by $- 4$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$

Step 3.1.5

Multiply $- 4 i \sin (\frac{π}{5}) (- 4 i \sin (\frac{π}{5}))$ .

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Step 3.1.5.1

Multiply $- 4$ by $- 4$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) + 16 i \sin (\frac{π}{5}) (i \sin (\frac{π}{5}))$

Step 3.1.5.2

Raise $i$ to the power of $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) + 16 (i^{1} i) \sin (\frac{π}{5}) \sin (\frac{π}{5})$

Step 3.1.5.3

Raise $i$ to the power of $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) + 16 (i^{1} i^{1}) \sin (\frac{π}{5}) \sin (\frac{π}{5})$

Step 3.1.5.4

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

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) + 16 i^{1 + 1} \sin (\frac{π}{5}) \sin (\frac{π}{5})$

Step 3.1.5.5

Add $1$ and $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) + 16 i^{2} \sin (\frac{π}{5}) \sin (\frac{π}{5})$

Step 3.1.5.6

Raise $\sin (\frac{π}{5})$ to the power of $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) + 16 i^{2} (\sin^{1} (\frac{π}{5}) \sin (\frac{π}{5}))$

Step 3.1.5.7

Raise $\sin (\frac{π}{5})$ to the power of $1$ .

$z^{2} + z (- 4 \cos (\frac{π}{5})) + z (- 4 i \sin (\frac{π}{5})) - 4 \cos (\frac{π}{5}) z + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) + 16 i^{2} (\sin^{1} (\frac{π}{5}) \sin^{1} (\frac{π}{5}))$

Step 3.1.5.8

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

Step 3.1.5.9

Add $1$ and $1$ .

Step 3.1.6

Rewrite $i^{2}$ as $- 1$ .

Step 3.1.7

Multiply $16$ by $- 1$ .

Step 3.2

Simplify by adding terms.

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Step 3.2.1

Move $\cos (\frac{π}{5})$ .

$z^{2} - 4 \cdot z \cos (\frac{π}{5}) - 4 z \cos (\frac{π}{5}) + z (- 4 i \sin (\frac{π}{5})) + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) - 16 \sin^{2} (\frac{π}{5})$

Step 3.2.2

Subtract $4 z \cos (\frac{π}{5})$ from $- 4 z \cos (\frac{π}{5})$ .

$z^{2} - 8 z \cos (\frac{π}{5}) + z (- 4 i \sin (\frac{π}{5})) + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) - 4 i \sin (\frac{π}{5}) z + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) - 16 \sin^{2} (\frac{π}{5})$

Step 3.2.3

Move $i$ .

$z^{2} - 8 z \cos (\frac{π}{5}) - 4 \cdot z i \sin (\frac{π}{5}) - 4 z i \sin (\frac{π}{5}) + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) - 16 \sin^{2} (\frac{π}{5})$

Step 3.2.4

Subtract $4 z i \sin (\frac{π}{5})$ from $- 4 z i \sin (\frac{π}{5})$ .

$z^{2} - 8 z \cos (\frac{π}{5}) - 8 z i \sin (\frac{π}{5}) + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) + 16 i \sin (\frac{π}{5}) \cos (\frac{π}{5}) - 16 \sin^{2} (\frac{π}{5})$

Step 3.2.5

Reorder the factors of $16 i \sin (\frac{π}{5}) \cos (\frac{π}{5})$ .

$z^{2} - 8 z \cos (\frac{π}{5}) - 8 z i \sin (\frac{π}{5}) + 16 \cos^{2} (\frac{π}{5}) + 16 \cos (\frac{π}{5}) i \sin (\frac{π}{5}) + 16 i \cos (\frac{π}{5}) \sin (\frac{π}{5}) - 16 \sin^{2} (\frac{π}{5})$

Step 4

Add $16 \cos (\frac{π}{5}) i \sin (\frac{π}{5})$ and $16 i \cos (\frac{π}{5}) \sin (\frac{π}{5})$ .

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Step 4.1

Move $\cos (\frac{π}{5})$ .

$z^{2} - 8 z \cos (\frac{π}{5}) - 8 z i \sin (\frac{π}{5}) + 16 \cos^{2} (\frac{π}{5}) + 16 i \cos (\frac{π}{5}) \sin (\frac{π}{5}) + 16 i \cos (\frac{π}{5}) \sin (\frac{π}{5}) - 16 \sin^{2} (\frac{π}{5})$

Step 4.2

Add $16 i \cos (\frac{π}{5}) \sin (\frac{π}{5})$ and $16 i \cos (\frac{π}{5}) \sin (\frac{π}{5})$ .

$z^{2} - 8 z \cos (\frac{π}{5}) - 8 z i \sin (\frac{π}{5}) + 16 \cos^{2} (\frac{π}{5}) + 32 i \cos (\frac{π}{5}) \sin (\frac{π}{5}) - 16 \sin^{2} (\frac{π}{5})$