Trigonometry Examples

$3 \cos (2 x)$

Step 1

Use the double-angle identity to transform $\cos (2 x)$ to $2 \cos^{2} (x) - 1$ .

$3 (2 \cos^{2} (x) - 1)$

Step 2

Apply the distributive property.

$3 (2 \cos^{2} (x)) + 3 \cdot - 1$

Step 3

Multiply.

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Step 3.1

Multiply $2$ by $3$ .

$6 \cos^{2} (x) + 3 \cdot - 1$

Step 3.2

Multiply $3$ by $- 1$ .

$6 \cos^{2} (x) - 3$