Precalculus Examples

$- \frac{7 π}{4}$

Step 1

Evaluate $\cos (- \frac{7 π}{4})$ .

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Step 1.1

Add full rotations of $2 π$ until the angle is greater than or equal to $0$ and less than $2 π$ .

$\cos (\frac{π}{4})$

Step 1.2

The exact value of $\cos (\frac{π}{4})$ is $\frac{\sqrt{2}}{2}$ .

$\frac{\sqrt{2}}{2}$

Step 2

Set up the coordinates $(\cos (θ), \sin (θ))$ .

$(\frac{\sqrt{2}}{2}, \frac{\sqrt{2}}{2})$