If x+y=z then find the value of cos^2x +cos^2y+cos^2 z

Dear student (1-sin^2 X) +(1-sin^2y) +(1-sin^2z)3-sin^2x-sin^2y-sin^2z3-sin^2(x+y+z)3-sin^2zBecause x+y=zThen by using componendo ÷ndo we solve this ans