化简:根号2cosa-根号2sina大神们帮帮忙

√(2 2cosa) =√(2 2(2cos^2(a/2)-1) =√(4cos^2(a/2)) =-2cos(a/2) 1 sina cosa =1 2sin(a/2)cos(a/2) 2cos^2(a/2)-1 =2cosa/2×(sina/2 cosa/2) (1 sina cosa)(sina/2-cosa/2)/√(2 2cosa) =[2cosa/2×(sina/2 cos...