Trigonometry Examples

$\cos (a + b) = (\frac{15}{17}) (\frac{- \sqrt{40}}{7}) + \frac{8}{17} (- \frac{3}{7})$

Step 1

The result can be shown in multiple forms.

Exact Form:

$\cos (a + b) = (\frac{15}{17}) (\frac{- \sqrt{40}}{7}) + \frac{8}{17} \cdot (- \frac{3}{7})$

Decimal Form:

$\cos (a + b) = - 0.99889352 \dots$

Step 2