Question 26157
f(x+h) = {{{(1-(x+h))/(x+h)}}}
f(x+h) = {{{(1-x-h))/(x+h)}}}


f(x+h) - f(x) = {{{ (1-x-h)/(x+h) - ((1-x)/x) }}}
f(x+h) - f(x) = {{{ (x(1-x-h) - (x+h)(1-x))/(x(x+h)) }}}
f(x+h) - f(x) = {{{ ((x-x^2-hx) - (x-x^2+h-hx))/(x^2 + hx) }}}
f(x+h) - f(x) = {{{ (x-x^2-hx-x+x^2-h+hx)/(x^2 + hx) }}}
f(x+h) - f(x) = {{{ (-h)/(x^2 + hx) }}}


(f(x+h) - f(x))/h = {{{ (-h)/(h(x^2 + hx)) }}}
(f(x+h) - f(x))/h = {{{ (-1)/(x^2 + hx) }}}
(f(x+h) - f(x))/h = {{{ (-1)/(x(x+h)) }}}


jon.