Question

先化简,再求值.X^2+X分之X^2-1除以(X-1-X分之X-1),其中X=2)

Answer 1

X^2+X分之X^2-1除以(X-1-X分之X-1),其中X=2)

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

=(x+1)(x-1)/x(x+1) / ((x-1)(1-1/x))

=(x-1)/x / ((x-1)((x-1)/x))

=(x-1)/x * x/(x-1)^2

=1/(x-1)

=1/(2-1)

=1