Trigonometry Examples

$\cos (\frac{7 π}{10}) \cos (\frac{8 π}{15}) + \sin (\frac{7 π}{10}) \sin (\frac{8 π}{15})$

Step 1

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{7 π}{10}) \cos (\frac{8 π}{15}) + \sin (\frac{7 π}{10}) \sin (\frac{8 π}{15})$

Decimal Form:

$0.86602540 \dots$