Question : What is the value of $\cos45° \sin15°$?
Option 1: $\frac{(\sqrt{3}-1)}{2}$
Option 2: $\frac{(\sqrt{3}-1)}{4}$
Option 3: $(\sqrt{3}+1)$
Option 4: $2 \sqrt{3}-1$
Latest: SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL complete guide
Correct Answer: $\frac{(\sqrt{3}-1)}{4}$
Solution :
$\cos 45° \sin 15°$
$=\frac{1}{2}[2\cos 45° \sin 15°]$
We know, $2\cos A\sin B=\sin(A+B)-\sin(A-B)$
$=\frac{1}{2}[\sin(45°+15°)-\sin(45°-15°)]$
$=\frac{1}{2}[\sin(60°)-\sin(30°)]$
$=\frac{1}{2}×[\frac{\sqrt3}{2}-\frac{1}{2}]$
$=\frac{1}{2}×\frac{\sqrt{3}−1}{2}$
$=\frac{\sqrt3-1}{4}$
Hence, the correct answer is $\frac{\sqrt3-1}{4}$.
Related Questions
Know More about
Staff Selection Commission Combined Grad ...
Answer Key | Eligibility | Application | Selection Process | Preparation Tips | Result | Admit Card
Get Updates Brochure
Your Staff Selection Commission Combined Graduate Level Exam brochure has been successfully mailed to your registered email id “”.
