Question

$[tex]f(x) = (frac{1}{x+1} + frac{1}{1-x} )(x+1) f( frac{2}{3} )$

Answer 1

$f(x) = (frac{1}{x+1} + frac{1}{1-x} )(x+1) \ f( frac{2}{3} )=(frac{1}{ frac{2}{3} +1} + frac{1}{1- frac{2}{3} } )( frac{2}{3} +1) =(frac{1}{ frac{5}{3}} + frac{1}{ frac{1}{3} } ) frac{5}{3} =(frac{3}{ 5}} +3 ) frac{5}{3} =1+5=6$
Ответ: 6