若sinα-cosα=(√2)/3,0
问题描述：
若sinα-cosα=(√2)/3,0
答
sinα-cosα=(√2)/3 平方可得 (sinα)^2+(cosα)^2 - 2sinαcosα=4/9因为(sinα)^2+(cosα)^2 =1 所以可知2sinαcosα = 1- 4/9 = 5/9所以(sinα+cosα)^2 = (sinα)^2+(cosα)^2 + 2sinαcosα = 1 + 5/9 = 14/9...