Finding a Quadratic Approximation for a Function

This can be used to try to visually find a best fit quadratic polynomial for a given function. The user must input the function and the tangent line approximation p1(x) at x = 0. The graph of the function and the tangent line will appear. Now use the slider for c to construct the graph of a quadratic function of the form p2(x) = p1(x) + c*x^2. Try to find a value for c that visually approximates the graph of the function the best.