1-cosA+cosB-cos(A+B) . A B tan-cot- 1+cosA-cosB-cos(A+B) cod-cod co- co co- ces -A ces

Prove that : 2cosA cosB = cos (A + B) + cos (A-B) .

cos^2 A + cos^2 B +cos^2 C=1+2cosA cosB cosC .

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

Ifsin(A-B)= sin A cosB-cos A sin B and cos(A-B) = cosA cosB + sin A sin B. Find the values of sin 15^@ and cos 15^@ .

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

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

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

If A-B=60^(@) then cos^(2)A+cos^(2)B-cosA cosB=