Question 312183
{{{ f(x)=4/(x+3)}}}
{{{ f(1)=4/4=1}}}
{{{ (f(x)-f(1))/(x-1)=(4/(x+3)-1)/(x-1)=((x+3)/(x+3))*((4/(x+3)-1)/(x-1))}}}
{{{ (f(x)-f(1))/(x-1)=(4-(x+3))/((x+3)(x-1))}}}
{{{ (f(x)-f(1))/(x-1)=(-x+1)/((x+3)(x-1))}}}
{{{ (f(x)-f(1))/(x-1)=-(x-1)/((x+3)(x-1))}}}
{{{ (f(x)-f(1))/(x-1)=(-cross((x-1)))/((x+3)cross((x-1)))}}}
{{{ (f(x)-f(1))/(x-1)=-1/(x+3)}}}