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在二次函数f(x)=ax^2+bx+c中,若b^2=2ac,且f(0)=-5,求f(x)的最值
人气:148 ℃ 时间:2020-03-31 21:48:31
解答
f(0)= 0 + 0 + c = c = -5所以,c = -5因为 b^2 = 2ac = -10aa = -b^2/10f(x)=ax^2 + bx + c = -(b^2/10)x^2 + bx - 5= -(1/10)(b^2x^2 - 10bx + 25) + 2.5 - 5= -(1/10)(bx - 5)^2 - 5/2当bx - 5 = 0时,取最大值.最...
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