x^3+1/x+1等于多少
x^3+1/x+1等于多少
x^3+1/x+1
=(x+1)(x^2-x+1)/(x+1)
=x^2-x+1
注：立方和公式：a^3+b^3=(a+b)(a^2-ab+b^2)
立方差公式：a^3-b^3=(a-b)(a^2+ab+b^2)
1/[1+1/(3+1/x)]=9/11 求X等于多少?
1/[1+1/(3+1/x)]=9/11
1/{1+1/[(3x+1)/x]}=9/11
1/[1+x/(3x+1)]=9/11
1/[(3x+1+x)/(3x+1)]=9/11
(3x+1)/(4x+1)=9/11
9(4x+1)=11(3x+1)
36x+9=33x+11
36x-33x=11-9
3x=2
x=2/3.
求解 x/(x+1)+x^2/(x+1)^2+x^3/(x+1)^3+x^4/(x+1)^4 等于多少
答：
x/(x+1)+x^2/(x+1)^2+x^3/(x+1)^3+x^4/(x+1)^4
1）x=0时，原式=0
2）x≠0时，各项形成首项为x/(x+1)，公比为x/(x+1)的等比数列
原式=[x/(x+1)]*{ [x/(x+1)]^4-1 } / [x/(x+1)-1]
=x{ 1- [x/(x+1)]^4 }
综上所述，原式=x{ 1- [x/(x+1)]^4 }
3+1/x+x=40 等于多少？急需
3+1/x+x=40
x²-37x=-1
x=无解
1/x-1/x+1等于多少
解：
通分求解：
1/x - 1/(x+1)
=[(x+1)-x]/[x(x+1)]
=1 / [x(x+1)]
（X+1）/X 等于多少?
（X+1）/X 等于1+ 1/x
化简（x³+3）/（x²-1）-（x+1）/（x-1）+1等于多少？
错了，第一个是x²+3
原式=(x²+3)/(x+1)(x-1)-(x+1)²/(x+1)(x-1)+(x+1)(x-1)/(x+1)(x-1)
=(x²+3-x²-2x-1+x²-1)/(x+1)(x-1)
=(x²-2x+1)/(x+1)(x-1)
=(x--1)²/(x+1)(x-1)
=(x-1)/(x+1)
∫（x+1）^3/x^2dx等于多少
∫（x+1）^3/x^2dx
=∫（x^3+3x^2+3x+1）/x^2dx
=∫（x+3+3/x+1/x^2)dx
=x^2/2+3x+3lnx-1/x+C
x+1=x/2等于多少
x+1/x=7 两边平方得： x2+1/x2+2=49 x2+1/x2=47 所以： (x^4+x^2+1)/x2 =x2+1+1/x2 =47+1 =48 倒数： x^2/(x^4+x^2+1) =1/48
(x+1/x^2)-(2x+1/x+1) 等于多少呀？
(x+1)/x^2-(2x+1)/(x+1)
=[(x+1)^2-(2x+1)x^2]/[(x+1)x^2]
=[x^2+2x+1-2x^3-x^2]/[(x+1)x^2]
=(1+2x-2x^3)/[(x+1)x^2].
