If `tan(A+B)=3tanA`, prove that
`sin(2A+B)=2sinB`

Prove that sin(A+B)sin(A-B)=sin^2A-sin^2B

If tan A=1//2,tanB=1//3 , then prove that cos 2A = sin 2B.

If A+B+C =pi prove that sin2A=-sin(2B+2C)

If tanA=18/17 and tanB=1/35 prove that tan(A-B)=1

Suppose A and B are angles lying in the first quadrant such that tanA=15/8 and tanB =12/5 .Prove that sin(A-B)=-21/221 and cos(A-B)=220/221

If sinA=sinBand cosA=cosB , then prove that " sin "(A-B)/(2)=0 .

For any DeltaABC , prove that (sin(B-C))/(sin(B+C))=(b^2-c^2)/(a^2)

For any triangle ABC, prove that (a+b)/c=cos((A-B)/2)/sin(C/2)

For any DeltaABC , prove that (a+b)/c=cos((A-B)/2)/sin(c/2)