Trigonometry Examples

$2 \cos (3 x)$

Step 1

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

$2 (4 \cos^{3} (x) - 3 \cos (x))$

Step 2

Apply the distributive property.

$2 (4 \cos^{3} (x)) + 2 (- 3 \cos (x))$

Step 3

Multiply.

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Step 3.1

Multiply $4$ by $2$ .

$8 \cos^{3} (x) + 2 (- 3 \cos (x))$

Step 3.2

Multiply $- 3$ by $2$ .

$8 \cos^{3} (x) - 6 \cos (x)$