1+sina=sin²(a/2)+cos²(a/2)+2sin(a/2)*cos(a/2)=[sin(a/2)+cos(a/2)]²,cosa=cos²(a/2)-sin²(a/2)=[cos(a/2)+sin(a/2)]*[cos(a/2)-sin(a/2)]那么1+sina+cosa=[cos(a/2)+sin(a/2)]*[cos(a/2...