Question

已知关于X的方程K²X²-2（K+1）X+1=0,有两个实数根

Answer 1

k^2x^2-2(k+1)x+1=0

x1+x2=-b/a=[2(k+1)]/k^2=4

x1*x2=1/k^2=1

x2/x1+x1/x2

=(x1^2+x2^2)/(x1*x2)

=[(x1+x2)^2-2x1*x2]/(x1*x2)

=(16-2)/1

=14/1

=14