Question

dada a função f(x) x+1 / x-1 calcule f( f(x) )

Answer 1

$f(x)=\frac{x+1}{x-1}\\\\f(f(x))=\frac{(\frac{x+1}{x-1})+1}{(\frac{x+1}{x-1})-1}\\\\f(f(x))=\frac{\frac{(x+1)+(x-1)}{x-1}}{\frac{(x+1)-(x-1)}{x-1}}\\\\f(f(x))=\frac{(x+1)+(x-1)}{(x+1)-(x-1)}\\\\f(f(x))=\frac{x+1+x-1}{x+1-x+1}\\\\f(f(x))=\frac{2x}{2}\\\\f(f(x))=x$