If sin (B + C-A)= 1, cos(C+ A- B)=1,.tan (A+ B - C)= 1 and if A,B,Care positive and acute angles, find A,B,C.

If sin A=3/5 , sin B=12/13 and sin C=7/25 where A,B,C are acute angles, find the value of sin (A + B + C).

If A + B + C = pi , prove that tan A+ tan B + tan C = tan A tan B tan C

If cos (A + B) sin (C + D)= cos (A - B) sin (C- D), prove that tanAtanBtanC = tanD

If A + B + C = pi , prove that sin 2A + sin 2B + sin 2C= 4 sin A sin B sin C

If A + B + C= pi and cos A = cos B cos C, show that tan A =tan B + tan C and cot B cot C=1/2.

If A + B + C= pi , prove that sin 2A + sin 2B -sin 2C =4cos A cos B sin C

If A + B + C = 2S, prove that sin (S- A) sin (S - B) +sin S sin (S-C) = sin A sin B

if A + B+ C= pi/2 ,show that tan A tan B + tan B tan C+ tan C tan A = 1

If (sec A + tan A)(sec B + tan B)(sec C + tan C) = (sec A- tan A)(sec B- tan B)(sec C tan C) Prove that each side is equal to +-1.

if A + B +C= pi/2 ,prove that cos(A - B - C)+ cos (B-C- A) + cos (C- A - B)= 4 cos A cos B cos C