х-100%
30-40%
х=(30*100)/40
х=75
Решение находится во вложениях!
f(x)' = (x^2/2x-1)' = ( (x^2)' (2x-1) -x^2*(2x-1)' ) / (2x-1)^2 =
= ( 2x (2x-1) - x^2*2 ) / (2x-1)^2 = ( 4x^2 -2x - 2 x^2 ) / (2x-1)^2 =
= ( 2x^2 -2x ) / (2x-1)^2 = 2x( x -1 ) / (2x-1)^2