(cosx)∧2+cos(x+120°)∧2+cos(x+240°)∧2的值为
问题描述:
(cosx)∧2+cos(x+120°)∧2+cos(x+240°)∧2的值为
答
cos(x+120°)∧2+cos(x+240°)∧2
化成cos(x-60°)∧2+cos(x+60°)∧2
再拆开
=1.5