Даю 17 баллов. Упростите выражения

cos x = cos 2.x/2 = cosˇ2(x/2)-sinˇ2(x/2)1) (1-2.cos(x/2) ; cosˇ2(x/2)- sinˇ2(x/2))/(1+2.cos(x/2)+cosˇ2(x/2) - sinˇ2 (x/2))=(cosˇ2(x/2)-2.cos(x/2) + cosˇ2 (x/2))/cosˇ2(x/2)+2.cos(x/2)+cosˇ(x/2)=(2.cosˇ2(x/2) - 2.cos(x/2))/2.cosˇ2(x/2)+2.cos(x/2) = (cos (x/2) -1)/cos(x/2)+12)(sin(x/2)-1)/(sin(x/2)+1)