求函数f(x)=(x+5)(x+2)/(x+1) （x

来源：学生作业帮助网编辑：作业帮时间：2024/05/10 09:33:30

求函数f(x)=(x+5)(x+2)/(x+1) （x
求函数f(x)=(x+5)(x+2)/(x+1) （x

求函数f(x)=(x+5)(x+2)/(x+1) （x
f(x)=(x+5)(x+2)/(x+1)
= (x+2)*[(x+1) + 4]/(x+1)
= (x+2)*[1 + 4/(x+1)]
= (x+2) + 4(x+2)/(x+1)
= (x+2) + 4[(x+1) + 1]/(x+1)
= (x+2) + 4[1 + 1/(x+1)]
= (x+2) + 4 + 4/(x+1)
= (x+1) + 4/(x+1) + 5
= -[-(x+1) - 4/(x+1)] + 5
x < -1,-(x+1) > 0 ,所以
-(x+1) + 4/[-(x+1)] ≥ 2 √[-(x+1)] * √[-4/(x+1)] = 4
-[-(x+1) - 4/(x+1)] ≤ -4
原式 ≤ -4 + 5 = 1
原式最大值为 1.
当 (x+1) = 4/(x+1) 时,取得最大值.,即
(x+1)^2 = 4,
x+1 = -2
x = -3

已知函数f(x)=3x²-5x+2,求f(f(x))= 设函数f(x)满足f(x-1)=2x-5,求f(x平方) 设函数f(x)满足f(x)+2f(1/x)=x,求f(x) 3f(x)+xf'(x)=5x平方+2x-3,f(x)为多项式函数, 求f(x) 函数f(x)满足f（x-1)=2x-5,求f(x),f(x²）, 已知函数f(x-2)=x^2-5x+1,求f(x)= 已知函数f(x-2)=2x^2-5x+1,求f(x) 函数````````````````````````` (5 15:3:7)f(x)+2+(-x)=2x 求f(x) 已知函数f(3x)=2x^2-5x+2.求f(x) 函数f(x)=x^2-2x+5,求f (x )值域已知函数f(2x-1)=4x²-6x+5,求f(x)? f(x)=4/5x-ln(1+x^2)求f(x)的导函数求函数f(x)=(x+5)(x+2)/(x+1) （x 求函数f(x)=(x+5)(x+2)/(x+1),(x＜-1)的最大值设函数f(x)=(x-1)(x-2)...(x-100)(x>100),求F'(X) ① f(x)为一次函数,且f[f(x)]=1+4x,求f(x)② f(x)+2f（-x）=3x+x平方 ,求f(x)③ f(x)为一次函数,且f(x+1)+f(x-1)=2x平方-4x+4,求f(x)④ f(2x-1)定义域（-1,5],求f(2-5x)定义域,求f(x)定义域⑤ f(x)定义域[0,2] ,求f(x平方) 已知函数f(x)=|x-2|-|x-5|求不等式f(x)≥x＾2-8x+15 已知二次函数f(x)满足f(3x+1)=9x^2-6x+5,求f(x)