Prove `(i)cos(A+B)+cos(A-B)=2cosAcosB` (ii)`cos(A-B)-cos(A+B)=2sinAsinB`

Prove (i)sin(A+B)+sin(A-B)=2sin A cos B (ii) sin(A+B)-sin(A-B)=2cos A sin B

For all values of angle A and B(i)cos(A-B)=cos A cos B+sin A sin B(ii)cos(A+B)=cos A cos B-sin A sin B

If A=60^(@) and B=30^(@) , verify that : (i)sin(A+B)=sinAcosB+cosAsinB (ii) cos(A+B)=cosAcosB-sinAsinB

If A=60^(@) and B=30^(@) , verify that : (i)sin(A-B)=sinAcosB-cosAsinB (ii) cos(A-B)=cosAcosB+sinAsinB (iii) tan(A-B)=(tanA-tanB)/(1+tanAtanB)

Prove that cos(A+B) cos(A-B)-sin(A+B) sin(A-B)=cos 2A.

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

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

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

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

cos^(2)(A-B)+cos^(2)B-2cos(A-B).cosA.cosB=?