c罗一人西班牙:如何求y=cos^2x+sinx的值域?
来源:百度文库 编辑:查人人中国名人网 时间:2024/05/14 10:23:34
Y
= (CosX)^2 + SinX
= -(SinX)^2 + SinX + 1
= -(SinX - 1/2)^2 + 5/4
0 <= (SinX - 1/2)^2 <= (-1 - 1/2)^2
0 <= (SinX - 1/2)^2 <= 9/4
-9/4 <= -(SinX - 1/2)^2 <= 0
-1 <= Y <= 5/4