3x的平方 5X 1=0 根与系数的积跟和
来源:学生作业帮助网 编辑:作业帮 时间:2024/04/28 18:45:56
3x平方-5x-6=0x1+x2=5/3,x1x2=-2(x1-x2)^2=(x1+x2)^2-4x1x2=25/9+8=97/9|x1-x2|=√(97/9)=√97/3x1-x2=±√97/3
即x1+x2=5/2x1x2=2/2=1所以x1²+x2²=(x1+x2)²-2x1x2=25/4-2=17/4所以原式=(x1²+x2²)/x1x2
x1x2=-1,x1+x2=3,x1的平方+x2的平方=(x1+x2)^2-2x1x2=11(1)x1的三次方*x2+x1*x2的三次方=x1x2(x1的平方+x2的平方)=-11(2)x1的平方分之
因为X1和X2是方程的两个根所以X1+X2=2|3X1.X2=-2|3(1)1/X1+1/X2=(X1+X2)|(X1.X2)=-1(2)X1的平方+X2的平方==(X1+X2)^2-2X1.X2=1
x1+x2=-2,x1x2=-3/2所以(1)(X1+X2)^2=(-2)^2=4(2)(X1+1)(X2+1)=x1x2+(x1+x2)+1=-3/2-2+1=-5/2(3)X1^2X2+X1X2^
“x1平方x2=x1x2平方1/x1平方=1/x2平方”两式里的“=”号应该是“+”号吧我就按“+”做了由韦达定理得x1+x2=-b/a=3x1x2=c/a=3/2则1.x1²x2+x1x2
方程为2x^2-5x+1=0x1+x2=-b/a=5/2x1x2=c/a=1/2(x1-3)(x2-3)=x1x2-3x1-3x2+9=x1x2-3(x1+x2)+9=1/2-3x5/2+9=2(x1
根据题意得x1+x2=-2x1x2=-3/2于是|x1-x2|²=(x1+x2)²-4x1x2=(-2)²-4×(-3/2)=4+6=10所以|x1-x2|=√10
(30+3根号5)/2或(30-3根号5)/2
x1+x2=3x1x2=-1则x1²+x2²=(x1+x2)²-2x1x2=9+2=111/x1²+1/x2²=(x1²+x2²)
由韦达定理:x1+x2=6/2=3,x1*x2=3/2,x1^2x2+x1x2^2=x1x2(x1+x2)=(3/2)*3=9/2,(x1+1/x2)(x2+1/x1)=x1x2+2+1/x1x2=3
化简原式为x1x2-3(x1+x2)+9x1x2=1/2x1+x2=-4/2=-2所以原式=31/2
x1+x2=-4/2=-2x1x2=-3/2所以(x1-x2)²=(x1+x2)²-4x1x2=4+6=10所以|x1-x2|=√10
1/x1平方+1/x2平方=(x1²+x2²)/x1²x2²=[(x1+x2)²-2x1x2]/x1²x2²x1+x2=-3,x1
解x1,x2是方程两根则有韦达定理有x1+x2=-3/4x1x2=-5/4∴(1)1/x1+1/x2=(x1+x2)/(x1x2)=(-3/4)×(-4/5)=3/5(2)x1²-x1x2+
X1+X2=3/2,X1*X2=-1/2,|X1-X2|=√(X1-X2)^2=√[(X1+X2)^2-4X1X2]=√(9/4+2)=√17/2,∴X1-X2=±√17/2.X2^2/X1+X1^2
X1^2=3-x1所以原式=3-x1+2x1+x2=3+x1+x2剩下的自己算吧
x1+x2=-a分之bx1*x2=a分之c配方a(x方+a分之bx)+c=0a(x+2a分之b)方-a分之b方+c=0解得x=2a分之-b加减根号下b方-4ac令x1=2a分之-b加根号下b方-4ac
x1+x2=-4/3x1x2=-7/31、x1²+x2²=(x1+x2)²-2x1x2=58/9所以x2/x1+x1/x2=(x1²+x2²)/x1x
把x=x1代入方程得3x1²-2x1-5=0,即3x1²-2x1=5由韦达定理可得:x1+x2=2/3所以3X1²-3X1-X2=3x1²-2x1-x1-x2=