求值
函数y=2sinx-cos2x的最大值是M,最小值是N,则M+N
y=2sinx-cos2x =2sinx -1+(2sinx)^2 =2[sinx +1/2]^2 - 3/2 ====>sinx=1 M =3 sinx = -1/2 N = -3/2 M+N =3/2
M根号5N负根号5M+N=0
答:怎样算函数y=cos2x加2sinx加1值域? y=cos2x+2sinx+1 =1-2sin^2 x+2sinx+1 =-2sin^2 x+2sinx+2 令...详情>>
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