Trigonometry Examples

\cos (- \frac{π}{4})

$\cos (- \frac{π}{4})$

Step 1

Add full rotations of

2 π

$2 π$ until the angle is greater than or equal to

0

$0$ and less than

2 π

$2 π$ .

\cos (\frac{7 π}{4})

$\cos (\frac{7 π}{4})$

Step 2

Apply the reference angle by finding the angle with equivalent trig values in the first quadrant.

\cos (\frac{π}{4})

$\cos (\frac{π}{4})$

Step 3

The exact value of

\cos (\frac{π}{4})

$\cos (\frac{π}{4})$ is

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

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

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

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

Step 4

The result can be shown in multiple forms.

Exact Form:

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

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

Decimal Form:

0.70710678 \dots

$0.70710678 \dots$

\cos (- \frac{π}{4})

$\cos (- \frac{π}{4})$

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