x² x的负二次方=7,求x x的负一次方-搜答案-智慧作业帮

已知x+x的负一次方=4,求x的平方+x的负二次方的值由已知：x+1/x=4可得：（x+1/x)^2=16x^+1/x^2=16-2=14

(x+1/x)²=5x²+1/x²+2=5x²+1/x²=5-2x²+1/x²=3即x²+x-²=3

x+x^-1=m两边平方x^2+2+x^-2=m^2x^2+x^-2=m^2-2

X^2+X^-2=3则：（X^2+X^-2）^2=9得到X^4+2+X^-4=9解得X^4+X^-4=7注：X^-2为X的-2次方,X^2为X的平方.望采纳

x^2-7x+1=0,∴x+1/x=7,∴x^2+x^(-2)=(x+1/x)^2-2=47.

化简可得3再问：怎么化简啊再答：(x2/y2)+(y2/x2)=[(xy+y2)/y2]+[(x2-xy)/x2]=(x/y)-(y/x)+2=[(x2-y2)/xy]+2=1+2=3化简可得3

令f(x)=-x^2+4x+5=(-x+5)(x+1)=0得x=5或x=-1;对称为x=2;(微分得2也可以)因为f(x)>=0；定义域[0,9]``值域[0,3]

X的负二次方图像

再问：X的负二分之一次方呢

x+1/x=3(x+1/x)^2=9x^2+1/x^2+2=9x^2+1/x^2=7x^2+1/x^2-2=7-2(x-1/x)^2=5x-1/x=±√5x^2-1/x^2=(x+1/x)(x-1/x

2x²-7x+2=0同除以x得：2x-7+2/x=02x+2/x=7x+1/x=7/2x²+x^-2=(x+1/x)²-2=（7/2）²-2=49/4-2=41

由题意得：x-3=-1X=4然后你自己应该会算吧

x+1/x=3(x+1/x)^2=9x^2+1/x^2+2=9x^2+1/x^2=7x^2+1/x^2-2=7-2(x-1/x)^2=5x-1/x=±√5x^2-1/x^2=(x+1/x)(x-1/x

1、x^3-5x^2-13x+2014=x(x^2-7x+1)+2(x^2-7x+1)+2012=20122、x^2-7x+1=0,显然x≠0同除x,x-7+1/x=0,x+1/x=7x^2+1/x^

（x+x负一次方）=9x的平方加x的负二次方+2=9x的平方加x的负二次方=7

x^2-4x+1=0x-4+1/x=0x+1/x=4x^2+1/x^2=(x+1/x)^2-2=4^2-2=16-2=14

正负三倍根号五好吧切鄙视你

x+1/x=M(x+1/x)^2=M^2x^2+2+1/x^2=M^2x^2+1/x^2=M^2-2

X+X\1=A(X+X\1)的平方=A的平方x的二次方+x的负二次方的值=A的平房-2

g(x+1/x)=(x+1/x)^2-2得g(x)=x^2-2f(x+1/x)=(x+1/x)(x^2-1+1/x^2)=(x+1/x)[(x+1/x)^2-3]得f(x)=x*(x^2-3)f(g(