Precalculus Examples

$\cos (\frac{π}{3} + \frac{π}{6})$

To write $\frac{π}{3}$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

$\cos (\frac{π}{3} \cdot \frac{2}{2} + \frac{π}{6})$

Write each expression with a common denominator of $6$ , by multiplying each by an appropriate factor of $1$ .

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Multiply $\frac{π}{3}$ by $\frac{2}{2}$ .

$\cos (\frac{π \cdot 2}{3 \cdot 2} + \frac{π}{6})$

Multiply $3$ by $2$ .

$\cos (\frac{π \cdot 2}{6} + \frac{π}{6})$

Combine the numerators over the common denominator.

$\cos (\frac{π \cdot 2 + π}{6})$

Simplify the numerator.

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Move $2$ to the left of $π$ .

$\cos (\frac{2 \cdot π + π}{6})$

Add $2 π$ and $π$ .

$\cos (\frac{3 π}{6})$

Cancel the common factor of $3$ and $6$ .

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Factor $3$ out of $3 π$ .

$\cos (\frac{3 (π)}{6})$

Cancel the common factors.

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Factor $3$ out of $6$ .

$\cos (\frac{3 π}{3 \cdot 2})$

Cancel the common factor.

$\cos (\frac{3 π}{3 \cdot 2})$

Rewrite the expression.

$\cos (\frac{π}{2})$

The exact value of $\cos (\frac{π}{2})$ is $0$ .

$0$