If the angles A, B and C of a triangle are in an arithmetic progression and if a, b and c denote the lengths of the sides opposite to A, B and C respectively, then the value of the expression is
- (A)
- (B)
- (C)1
- (D)✓ Correct
Answer: (D)
Solution
Since A, B, C are in AP, we have . Also, , so , giving .
Using the sine rule: , so .
The expression becomes:
Since :
Using the sine rule: , so .
The expression becomes:
Since :
JEE Advanced · 2010 · 11 Apr 2010 · Paper 1 · Single correct option