Question

计算：（x-2/x+2加上x/x^2-4）除以1/x^2-4 计算：1/x+1加上1/x-1 计算：a+1/a-1减去a

Answer 1

（x-2/x+2加上x/x^2-4）除以1/x^2-4

=（x²-4x+4+x)/(x-2)(x+2)×(x-2)(x+2)

=x²-3x+4

1/x+1加上1/x-1

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

=2x/(x²-1)

a+1/a-1减去a^2+a/a^2-1

=(a+1)²/(a-1)(a+1)-(a²+a)/(a-1)(a+1)

=(a²+2a+1-a²-a)/(a-1)(a+1)

=(a+1)/(a-1)(a+1)

=1/(a-1)