4x=34-2x x
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由于f(x)=2xx+1,则f(1x)=2x1x+1=21+x,∴f(x)+f(1x)=2.∴f(12008)+f(12007)+…+f(12)+f(1)+f(2)+…+f(2008)=[f(1200
随便给个答案3+84+975=1062
∵f′(x)=4(1-x2)(x2+1)2,令f′(x)>0,解得-1<x<1∴函数f(x)的递增区间为(-1,1).又∵f(x)在(m,2m+1)上单调递增,∴m≥-12m+1≤1,解得-1≤m≤0
∵x2+1>0恒成立,∴函数的定义域为R.若x=0,则f(x)=0,若x≠0时,f(x)=2xx2+1=2x+1x,若x>0,x+1x≥2x•1x=2,此时0<2x+1x≤1,若x<0,则x+1x≤−
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(2x+3)(x-4)-(x+2)(x-3)=x^2+6(2x^2-5x-12)-(x^2-x-6)=x^2+62x^2-5x-12-x^2+x+6=x^2+6-4x-12=04x=-12x=-3
5x-1=4x5x-4x=1x=1
3x(x+2)+(x+1)(x-1)=4(xx+2)3x²+6x+x²-1=4x²+86x=8+16x=9x=3/2
方程左边1/(xx+x)+1/(xx+3x+2)+1/(xx+5x+6)+1/(xx+7x+12)+1/(xx+9x+20)对分母因式分解得1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(
x和乘号混淆了360=2X2X2X3X3X52X2=42X3=636=3X4X5X6所以x=3
去分母:(2-x)=x-3+1,化简得:2x=4,∴x=2,经检验,原分式方程的根是:x=2.
(x−2x+2+4xx2−4)÷1x2−4,=x2−4+4xx2−4×(x2-4),=x2+4x-4,当x=-3时,原式=9-12-4=-7.
2/9再问:过程,谢谢再答:由题目得y/x=2/3xy/xx+yy-yy/xx-yy=y/x-(y/x)²=2/3-4/9=2/9
由2−xx−1≥0,得1<x≤2,即A={x|1<x≤2}.∵y=3x是R上的增函数,∴由32ax<3a+x,得2ax<a+x,∴B={x|(2a-1)x<a},(1)当2a-1>0,即a>12时,B
xx+yy+4x-6y+13=0整理得:(x+2)^2+(y-3)^2=0那么只有(x+2)=0(y-3)=0x=-2y=3(x^2-2x)/(x^2+3y^2)=(4+4)/(4+3*9)=8/31
x^2+x-x^2-y=3x-y=3(x-y)^2=9x^2+y^2-2xy=9(x^2+y^2)/2-xy=9/2
不可能,题目是错的XX3+XX6≠XXX33+6≠xx3
(1)27*3=816*9=54(2)56/7=89/3=12/4
x(x+1)-(xx+y)=-3x^2+x-x^2-y=-3x-y=-3(xx+yy)/2-xy=(x^2+y^2-2xy)/2=(x-y)^2/2=(-3)^2/2=9/2再问:是对的吧!再答:当然