Question

1、 X/X^2+X+1=a(a不等于0,1/2) 求 x^2/x^4+x^2+1

Answer 1

1.x^2/x^4+x^2+1=(x/x^2+x)^2-1=(a-1)^2-1=a^2-2a.

2.x=4ab/a+b?还是x=4ab/(a+b)?

(x+2a/x-2a)+(x+2b/x-2b) 还是(x+2a/x-2a)*(x+2b/x-2b)

3.a/x+b/y+c/z=0 两边乘以xyz得 ayz+bxz+cxy=0,

再除以abc得 yz/bc+xz/ac+xy/ab=0.

1=(x/a+y/b+z/c)^2=x^2/a^2 + y^2/b^2 + z^2/c^2+2(yz/bc+xz/ac+xy/ab)

=x^2/a^2 + y^2/b^2 + z^2/c^2,即为所求.