Question

@ If A+B+C =
and if none of A, B, C is an odd multiple of
2
then prove that
(a) cot A + cot B + cot C = cot A cot B cot C
(b)tan A tan B + tan B tan C + tan C tan A = 1 and hence show that
(c)cos (B+C)
Σ
cos B cos C
= 2.​

Answer 1

Answer:

see the image will be helpful for you