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

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

cos(A-B)=cosAcosB+sinA sinB

Prove (i)sin(A+B)+sin(A-B)=2sin A cos B (ii) sin(A+B)-sin(A-B)=2cos 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=30^@ and B=60^@ , 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.

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

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