Let , where are angles of a triangle . If the lengths of the sides opposite these angles are respectively, then :
- (A)
- (B) are in A.P
- (C) are in A.P
- (D) are in A.P.✓ Correct
Answer: (D)
Solution
Cross-multiplying, . Expanding and collecting gives , and since , . Replacing sines by sides and using ,
so . Thus are in arithmetic progression.
so . Thus are in arithmetic progression.
JEE Main · 2021 · 27 Aug 2021 · Shift 1 · Single correct option