prove that `cos(A+B)=cosAcosB-sinAsinB`

cos(A-B)=cosAcosB+sinA sinB

If A=B=45^(@) , show that : cos(A+B)=cosAcosB-sinAsinB

If A=30^@ and B=60^@ ,show that (ii)cos(A+B)=cosAcosB-sinAsinB

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)

If sin(A+B)=sinAcosB+cosAsinB and cos(A-B)=cosAcosB+sinAsinB , find the values of (i) sin75^(@) and (ii) cos15^(@) .

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

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