Trigonometry Examples

$\cos (3 x) - \cos (x)$

Step 1

Use the triple-angle identity to transform $\cos (3 x)$ to $4 \cos^{3} (x) - 3 \cos (x)$ .

$4 \cos^{3} (x) - 3 \cos (x) - \cos (x)$

Step 2

Subtract $\cos (x)$ from $- 3 \cos (x)$ .

$4 \cos^{3} (x) - 4 \cos (x)$