If `sinA+sinB=a and cosA+cosB=b,then cos(A+B)`

If sinA+sinB=a and cosA+cosB=b, show that cos(A+B) = (b^2-a^2)/(b^2+a^2)

If sinA+sinB=l and cosA-cosA-cosB=m , then cos(A-B)=

If sinA+sinB=a and cosA+cosB=b, show that sin(A+B) = (2ab)/(b^2+a^2)

If sinA = sinB and cosA=cosB, then which one of the following is correct ?

If sinA+sinB=a and cosA+cosB=b, show that tan(A+B) = (2ab)/(b^2-a^2)

If sinA = sinB and cosA = cosB then prove that, either A=B or they differ by multiples of four right angles.

If sinA+cosB=a and sinB+cosA=b then sin(A+B)=