In any `DeltaABC`, prove that `4(bc cos^(2)\"\"A/2+ca cos^(2)\"\"B/2+ab cos^(2)\"\"C/2)=(a+b+c)^(2)`
Channel: Doubtnut
Date: 2020-01-03

In any `DeltaABC`, prove that `4(bc cos^(2)\"\"A/2+ca cos^(2)\"\"B/2+ab cos^(2)\"\"C/2)=(a+b+c)^(2)`