已知a b是两个非零向量,且满足（a﹣2b）垂直于a,（b－2b）垂直于b,则a...

a与b夹角 = x(a-2b)。a =0|a|^2-2a。b =0 (1)(b-2a)。b = 0|b|^2 -2a。b =0 (2)=> |a| =|b|from (1)cosx =|a|^2/(2|a||b|) = 1/2x =π/3