Question 968215
{{{f(x)=1/x}}}
{{{f(x+h)=1/(x+h)}}}
{{{f(x+h)-f(x)=1/(x+h)-1/x}}}
{{{f(x+h)-f(x)=x/(x(x+h))-(x+h)/(x(x+h))}}}
{{{f(x+h)-f(x)=(x-x-h)/(x(x+h))}}}
{{{highlight_green(f(x+h)-f(x)=(-h)/(x(x+h)))}}}