Question
Question: In any triangle \(ABC\sin^{2}\frac{A}{2} + \sin^{2}\frac{B}{2} + \sin^{2}\frac{C}{2}\) is equal to...
In any triangle ABCsin22A+sin22B+sin22C is equal to
A
1−2cos2Acos2Bcos2C
B
1−2sin2Acos2Bcos2C
C
1−2sin2Asin2Bsin2C
D
1−2cos2Acos2Bsin2C
Answer
1−2sin2Asin2Bsin2C
Explanation
Solution
Sol. Trick: For A=B=C=60o only option (3) satisfies the
condition.