Precalculus Examples

$\cos (\frac{3 π}{2} - π)$

Step 1

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

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

Step 2

Combine fractions.

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Step 2.1

Combine $- π$ and $\frac{2}{2}$ .

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

Step 2.2

Combine the numerators over the common denominator.

$\cos (\frac{3 π - π \cdot 2}{2})$

Step 3

Simplify the numerator.

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Step 3.1

Multiply $2$ by $- 1$ .

$\cos (\frac{3 π - 2 π}{2})$

Step 3.2

Subtract $2 π$ from $3 π$ .

$\cos (\frac{π}{2})$

Step 4

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

$0$