1+cosa-sinb+sinasinb=01+cosa=sinb-sinasinb=sinb(1-sina).(1) 1-cosa-cosb+sinacosb=0 1-cosa=cosb-sinacosb=cosb(1-sina).(2)(1)^2+(2)^2(1-cosa)^2+(1+cosa)^2=(1-sina)^22+2cos^2a=1-2sina+sin^2a4-2sin^2a=1-2...