The identity $\sin 2A$ equals:
- $2\sin A\cos A$, the standard double-angle formula on the chart
- $\sin^2 A + \cos^2 A$, equal to $1$ by Pythagorean identity
- $2\sin^2 A$, missing the cosine factor in the formula
- $\sin A + \cos A$, the simple sum of the trig functions
Show answer and solution
Correct answer: A. $2\sin A\cos A$, the standard double-angle formula on the chart
Double-angle: $\sin 2A = 2\sin A\cos A$.