（1+sinx+cosx）/（sinx/2+cosx/2）化简

分子=[sin²(x/2)+cos²(x/2)]+2sin(x/2)cos(x/2)+[cos²(x/2)-sin²(x/2)]
=[cos(x/2)+sin(x/2)]²+[cos(x/2)-sin(x/2)][cos(x/2)+sin(x/2)]
=[cos(x/2)+sin(x/2)][cos(x/2)+sin(x/2)+cos(x/2)-sin(x/2)]
=[cos(x/2)+sin(x/2)][2cos(x/2)]
分母=cos(x/2)+sin(x/2)
所以原式=2cos(x/2)