函数y=[sin(a/2)]/(1+cosa)其中,0＜a＜π/2.换元.可设x=sin(a/2).易知,0＜x＜(√2)/2.且1+cosa=1+1-2sin²(a/2)=2-2x².∴函数y=x/(2-2x²)2y=x/(1-x²).-1/(2y)=x-(1/x).易知,x-(1/x)在区间(0,√2/...