函数y=4sin^2(x)+6cosx-6(-π/3≤x≤2π/3)的值域
回复(1) 2009-03-12 21:45 来自版块 - 
表情
zhyxlyfy=4sin^2x+6cosx-6 =4-4cos^2x+6cosx-6 =-4cos^2x+6cosx-2 令a=cosx 负三分之派小于等于x小于等于三分之二派 则-1/2<=a<=1 y=-4a^2+6a-2 =-4(a-3/4)^2...(2009-03-12 21:55)

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