`f(x) = (x^2)/(x - 1)` Determine the point(s) at which the graph of the function has a horizontal tangent line.
Find the derivative of the function using the Quotient Rule. Set the derivative equal to 0 and solve for the x value(s). When the derivative is equal to zero, the slope of the tangent line is horizontal to the graph.
Plug in the critical x value(s) into the original function.
` ` `f(2)=2^2/(2-1)=4`
The function will have horizontal lines at the points (0,0) and (2,4).