Quantitative Aptitude Ques 432
Question: If A, B and C are the angles of a $ \Delta ABC, $ then following is equal to $ ( \frac{B+C}{2} ) $
Options:
A) $ cosec\frac{A}{2} $
B) $ \cos \frac{A}{2} $
C) $ \sec \frac{A}{2} $
D) $ \sec \frac{B}{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
- A, B and C are angles of a triangle.
$ \therefore $ $ \angle A+\angle B+\angle C=180{}^\circ $ $ \sin ( \frac{B+C}{2} )=\sin ( \frac{A+B+C}{2}-\frac{A}{2} ) $ $ =\sin ( 90{}^\circ -\frac{A}{2} )=\cos \frac{A}{2} $
BETA
