Question

Find the value of $2cos45^{\circ}\, sin15^{\circ}$.

• A. $\frac{\sqrt{3}+1}{2}$
• B. $1/2$
• C. $\frac{\sqrt{3}-1}{2}$
• D. $\frac{\sqrt{3}}{2}$

Answer 1

Answer: (C)

We have, $2cos45^{\circ}\, sin15^{\circ}$
$= sin(45^{\circ} + 15^{\circ}) - sin(45^{\circ} - 15^{\circ})$
$=sin60^{\circ}-sin30^{\circ}=\frac{\sqrt{3}-1}{2}$