Trigonometry Examples

{cos}^{2} (\frac{2 π}{11}) - {sin}^{2} (\frac{2 π}{11})

$\cos^{2} (\frac{2 π}{11}) - \sin^{2} (\frac{2 π}{11})$

Step 1

Apply the cosine double-angle identity.

$\cos (2 \frac{2 π}{11})$

Step 2

Multiply

$2 \frac{2 π}{11}$ .

Tap for more steps...

Step 2.1

Combine

$2$ and

$\frac{2 π}{11}$ .

$\cos (\frac{2 (2 π)}{11})$

Step 2.2

Multiply

$2$ by

$2$ .

$\cos (\frac{4 π}{11})$

Step 3

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{4 π}{11})$

Decimal Form:

$0.41541501 \dots$