Trigonometry Examples

$\cos (\frac{13 π}{18}) \cos (\frac{17 π}{36}) + \sin (\frac{13 π}{18}) \sin (\frac{17 π}{36})$

Step 1

The result can be shown in multiple forms.

Exact Form:

$\cos (\frac{13 π}{18}) \cos (\frac{17 π}{36}) + \sin (\frac{13 π}{18}) \sin (\frac{17 π}{36})$

Decimal Form:

$0.70710678 \dots$