已知函数y=cos2x+sin^2-cosx.求最大值与最小值_数学解答

已知函数y=cos2x+sin^2-cosx.求最大值与最小值

人气：461 ℃　时间：2019-10-19 16:17:21

解答

cos2x=cos^2-sin^2
cos2x+sin^2-cosx
=cos^2-sin^2+sin^2-cosx
=cos^2-cosx
=cos^2-cosx+1/4-1/4
=(cosx-1/2)^2-1/4
-1