化简X的²-2X 1分之X的平方-1×X的平方 X分之X-1 X分之2=
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/04 01:06:13
5x²+x-5=0两根x1,x2,由韦达定理得x1+x2=-1/5x1x2=-5/5=-1x1²+x2²=(x1+x2)²-2x1x2=(-1/5)²
X1+X2=-B/A=2X1*X2=C/A=1/2求得X1=1+根号2或者X1=1-根号2从而求出X2的值X1/X2+X2/X1=(X1*X1+X2*X2)/(X1X2)=6
2x²-3/4(4x-6x²)+(x-3x²)=2x²-3x+9/2x²+x-3x²=7/2x²-2x
∵x²+6x+3=0∴x1+x2=-6x1x2=3x1/x2+x2/x1=(x1+x2)²-2x1x2/x1x2=10
x的平方-9分之x的平方+2x-3乘x的平方-1分之x的平方-5x+6=(x-3)分之(x-1)乘[(x-1)(x+1)]分之(x-2)(x-3)=(x+1)分之(x-2)
x1+x2=4x1x2=1/2原式=(x1+x2)²÷(x1+x2)/x1x2=x1x2(x1+x2)=2
=2x/x²-(2x-1)/x²=(2x-2x+1)/x²=1/x²
1/x1+1/x2=(x1+x2)/x1x2伟达定理x1+x2=-b/ax1x2=c/a1-2
再答:还是再答:
设x1,x2是方程2x平方+4x-3=0的两个根,则x1+x2=-2x1·x2=-3/2∴x1平方+x2平方=(x1+x2)²-2x1·x2=(-2)²-2×(-3/2)=4+3=
2x平方-5x-1=0X平方-5/2X-1/2=0X平方-5/2X=1/2X平方-5/2X+5/4的平方=1/2+5/4的平方(X-5/4)平方=33/16X-5/4=正负根号33/4X=正负根号33
=x/(x+2)(x-2)-(x-2)/(x+2)(x-2)=[x-(x-2)]/(x+2)(x-2)=2/(x²-4)
(x-5分之x-5-x分之x)\x的平方-25分之2x=2x/(x-5)*(x-5)(x+5)/2x=x+5
再问:那个题不是这样的。是再答:再问:带入麻烦写一下,谢谢再答:什么叫合适的代入,最大值最小值?还是别的再问:然后从-根号下5小于x小于根号下5中选择一个合适的带入再答:可以x=21/(x+2)=1/
x1+x2=-3/2x1x2=-21/x1+1/x2=(x1+x2)/x1x2=(-3/2)/(-2)=3/4x1²+x2²=(x1+x2)²-2x1x2=(-3/2)&
X1+X2=-6/2=-3X1*X2=-3/21/X1+1/X2=(X1+X2)/(X1X2)=-3/(-3/2)=2
原式=(x+2)²/(x+2)(x-2)-x/(x-2)=(x+2)/(x-2)-x/(x-2)=2/(x-2)
x1+x2=4x1x2=-1(x1+x2)^2/(1/x1+1/x2)=(x1+x2)^2*x1x2/(x1+x2)=x1x2*(x1+x2)=-4
原式=[2x(x+1)/(x+1)(x-1)-x(x-1)/(x-1)²]÷x/(x+1)=[2x/(x-1)-x/(x-1)]×(x+1)/x=x/(x-1)×(x+1)/x=(x+1)/
2x²+5x-3=0(2X-1)(X+3)=0所以有X1=1/2X2=-3或者X1=-3X2=1/2则|x1-x2|=3.51/x1²+1/x2²=4+1/9=37/9