Trigonometry Examples

tan (165)

$\tan (165)$

Apply the reference angle by finding the angle with equivalent trig values in the first quadrant. Make the expression negative because tangent is negative in the second quadrant.

- tan (15)

$- \tan (15)$

Split

15

$15$ into two angles where the values of the six trigonometric functions are known.

- tan (45 - 30)

$- \tan (45 - 30)$

Separate negation.

- tan (45 - (30))

$- \tan (45 - (30))$

Apply the difference of angles identity.

- \frac{tan (45) - tan (30)}{1 + tan (45) tan (30)}

$- \frac{\tan (45) - \tan (30)}{1 + \tan (45) \tan (30)}$

The exact value of

tan (45)

$\tan (45)$ is

1

$1$ .

- \frac{1 - tan (30)}{1 + tan (45) tan (30)}

$- \frac{1 - \tan (30)}{1 + \tan (45) \tan (30)}$

The exact value of

tan (30)

$\tan (30)$ is

\frac{\sqrt{3}}{3}

$\frac{\sqrt{3}}{3}$ .

- \frac{1 - \frac{\sqrt{3}}{3}}{1 + tan (45) tan (30)}

$- \frac{1 - \frac{\sqrt{3}}{3}}{1 + \tan (45) \tan (30)}$

The exact value of

tan (45)

$\tan (45)$ is

1

$1$ .

- \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 tan (30)}

$- \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \tan (30)}$

The exact value of

tan (30)

$\tan (30)$ is

\frac{\sqrt{3}}{3}

$\frac{\sqrt{3}}{3}$ .

- \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}}

$- \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}}$

Simplify

- \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}}

$- \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}}$ .

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Multiply the numerator and denominator of the complex fraction by

3

$3$ .

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Multiply

\frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}}

$\frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}}$ by

\frac{3}{3}

$\frac{3}{3}$ .

- ⎛ ⎜ ⎝ \frac{3}{3} \cdot \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}} ⎞ ⎟ ⎠

$- (\frac{3}{3} \cdot \frac{1 - \frac{\sqrt{3}}{3}}{1 + 1 \frac{\sqrt{3}}{3}})$

Combine.

- \frac{3 (1 - \frac{\sqrt{3}}{3})}{3 (1 + 1 \frac{\sqrt{3}}{3})}

$- \frac{3 (1 - \frac{\sqrt{3}}{3})}{3 (1 + 1 \frac{\sqrt{3}}{3})}$

- \frac{3 (1 - \frac{\sqrt{3}}{3})}{3 (1 + 1 \frac{\sqrt{3}}{3})}

$- \frac{3 (1 - \frac{\sqrt{3}}{3})}{3 (1 + 1 \frac{\sqrt{3}}{3})}$

Apply the distributive property.

- \frac{3 \cdot 1 + 3 (- \frac{\sqrt{3}}{3})}{3 \cdot 1 + 3 (1 \frac{\sqrt{3}}{3})}

$- \frac{3 \cdot 1 + 3 (- \frac{\sqrt{3}}{3})}{3 \cdot 1 + 3 (1 \frac{\sqrt{3}}{3})}$

Cancel the common factor of

3

$3$ .

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Move the leading negative in

- \frac{\sqrt{3}}{3}

$- \frac{\sqrt{3}}{3}$ into the numerator.

- \frac{3 \cdot 1 + 3 \frac{- \sqrt{3}}{3}}{3 \cdot 1 + 3 (1 \frac{\sqrt{3}}{3})}

$- \frac{3 \cdot 1 + 3 \frac{- \sqrt{3}}{3}}{3 \cdot 1 + 3 (1 \frac{\sqrt{3}}{3})}$

Cancel the common factor.

$- \frac{3 \cdot 1 + 3 \frac{- \sqrt{3}}{3}}{3 \cdot 1 + 3 (1 \frac{\sqrt{3}}{3})}$

Rewrite the expression.

$- \frac{3 \cdot 1 - \sqrt{3}}{3 \cdot 1 + 3 (1 \frac{\sqrt{3}}{3})}$

Multiply

$3$ by

$1$ .

$- \frac{3 - \sqrt{3}}{3 \cdot 1 + 3 \cdot 1 \frac{\sqrt{3}}{3}}$

Simplify the denominator.

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Multiply

$3$ by

$1$ .

$- \frac{3 - \sqrt{3}}{3 + 3 \cdot 1 \frac{\sqrt{3}}{3}}$

Cancel the common factor of

$3$ .

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Factor

$3$ out of

$3 \cdot 1$ .

$- \frac{3 - \sqrt{3}}{3 + 3 (1) \frac{\sqrt{3}}{3}}$

Cancel the common factor.

$- \frac{3 - \sqrt{3}}{3 + 3 \cdot 1 \frac{\sqrt{3}}{3}}$

Rewrite the expression.

$- \frac{3 - \sqrt{3}}{3 + \sqrt{3}}$

Multiply

$\frac{3 - \sqrt{3}}{3 + \sqrt{3}}$ by

$\frac{3 - \sqrt{3}}{3 - \sqrt{3}}$ .

$- (\frac{3 - \sqrt{3}}{3 + \sqrt{3}} \cdot \frac{3 - \sqrt{3}}{3 - \sqrt{3}})$

Multiply

$\frac{3 - \sqrt{3}}{3 + \sqrt{3}}$ by

$\frac{3 - \sqrt{3}}{3 - \sqrt{3}}$ .

$- \frac{(3 - \sqrt{3}) (3 - \sqrt{3})}{(3 + \sqrt{3}) (3 - \sqrt{3})}$

Expand the denominator using the FOIL method.

$- \frac{(3 - \sqrt{3}) (3 - \sqrt{3})}{9 - 3 \sqrt{3} + \sqrt{3} \cdot 3 - {\sqrt{3}}^{2}}$

Simplify.

$- \frac{(3 - \sqrt{3}) (3 - \sqrt{3})}{6}$

Simplify the numerator.

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Raise

$3 - \sqrt{3}$ to the power of

$1$ .

$- \frac{{(3 - \sqrt{3})}^{1} (3 - \sqrt{3})}{6}$

Raise

$3 - \sqrt{3}$ to the power of

$1$ .

$- \frac{{(3 - \sqrt{3})}^{1} {(3 - \sqrt{3})}^{1}}{6}$

Use the power rule

$a^{m} a^{n} = a^{m + n}$ to combine exponents.

$- \frac{{(3 - \sqrt{3})}^{1 + 1}}{6}$

Add

$1$ and

$1$ .

$- \frac{{(3 - \sqrt{3})}^{2}}{6}$

Rewrite

${(3 - \sqrt{3})}^{2}$ as

$(3 - \sqrt{3}) (3 - \sqrt{3})$ .

$- \frac{(3 - \sqrt{3}) (3 - \sqrt{3})}{6}$

Expand

$(3 - \sqrt{3}) (3 - \sqrt{3})$ using the FOIL Method.

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Apply the distributive property.

$- \frac{3 (3 - \sqrt{3}) - \sqrt{3} (3 - \sqrt{3})}{6}$

Apply the distributive property.

$- \frac{3 \cdot 3 + 3 (- \sqrt{3}) - \sqrt{3} (3 - \sqrt{3})}{6}$

Apply the distributive property.

$- \frac{3 \cdot 3 + 3 (- \sqrt{3}) - \sqrt{3} \cdot 3 - \sqrt{3} (- \sqrt{3})}{6}$

Simplify and combine like terms.

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Simplify each term.

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Multiply

$3$ by

$3$ .

$- \frac{9 + 3 (- \sqrt{3}) - \sqrt{3} \cdot 3 - \sqrt{3} (- \sqrt{3})}{6}$

Multiply

$- 1$ by

$3$ .

$- \frac{9 - 3 \sqrt{3} - \sqrt{3} \cdot 3 - \sqrt{3} (- \sqrt{3})}{6}$

Multiply

$3$ by

$- 1$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} - \sqrt{3} (- \sqrt{3})}{6}$

Multiply

$- \sqrt{3} (- \sqrt{3})$ .

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Multiply

$- 1$ by

$- 1$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + 1 \sqrt{3} \sqrt{3}}{6}$

Multiply

$\sqrt{3}$ by

$1$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + \sqrt{3} \sqrt{3}}{6}$

Raise

$\sqrt{3}$ to the power of

$1$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + {\sqrt{3}}^{1} \sqrt{3}}{6}$

Raise

$\sqrt{3}$ to the power of

$1$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + {\sqrt{3}}^{1} {\sqrt{3}}^{1}}{6}$

Use the power rule

$a^{m} a^{n} = a^{m + n}$ to combine exponents.

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + {\sqrt{3}}^{1 + 1}}{6}$

Add

$1$ and

$1$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + {\sqrt{3}}^{2}}{6}$

Rewrite

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

$3$ .

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Use

$\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite

$\sqrt{3}$ as

$3^{\frac{1}{2}}$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + {(3^{\frac{1}{2}})}^{2}}{6}$

Apply the power rule and multiply exponents,

${(a^{m})}^{n} = a^{m n}$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + 3^{\frac{1}{2} \cdot 2}}{6}$

Combine

$\frac{1}{2}$ and

$2$ .

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + 3^{\frac{2}{2}}}{6}$

Cancel the common factor of

$2$ .

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Cancel the common factor.

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + 3^{\frac{2}{2}}}{6}$

Rewrite the expression.

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + 3^{1}}{6}$

Evaluate the exponent.

$- \frac{9 - 3 \sqrt{3} - 3 \sqrt{3} + 3}{6}$

Add

$9$ and

$3$ .

$- \frac{12 - 3 \sqrt{3} - 3 \sqrt{3}}{6}$

Subtract

$3 \sqrt{3}$ from

$- 3 \sqrt{3}$ .

$- \frac{12 - 6 \sqrt{3}}{6}$

Cancel the common factor of

$12 - 6 \sqrt{3}$ and

$6$ .

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Factor

$6$ out of

$12$ .

$- \frac{6 \cdot 2 - 6 \sqrt{3}}{6}$

Factor

$6$ out of

$- 6 \sqrt{3}$ .

$- \frac{6 \cdot 2 + 6 (- \sqrt{3})}{6}$

Factor

$6$ out of

$6 (2) + 6 (- \sqrt{3})$ .

$- \frac{6 (2 - \sqrt{3})}{6}$

Cancel the common factors.

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Factor

$6$ out of

$6$ .

$- \frac{6 (2 - \sqrt{3})}{6 (1)}$

Cancel the common factor.

$- \frac{6 (2 - \sqrt{3})}{6 \cdot 1}$

Rewrite the expression.

$- \frac{2 - \sqrt{3}}{1}$

Divide

$2 - \sqrt{3}$ by

$1$ .

$- (2 - \sqrt{3})$

Apply the distributive property.

$- 1 \cdot 2 - - \sqrt{3}$

Multiply

$- 1$ by

$2$ .

$- 2 - - \sqrt{3}$

Multiply

$- - \sqrt{3}$ .

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Multiply

$- 1$ by

$- 1$ .

$- 2 + 1 \sqrt{3}$

Multiply

$\sqrt{3}$ by

$1$ .

$- 2 + \sqrt{3}$

The result can be shown in multiple forms.

Exact Form:

$- 2 + \sqrt{3}$

Decimal Form:

$- 0.26794919 \dots$