33.2.Show that the point at which the tangent to the curve y = f(x) intersects the y axis is (0, f(x) - xf'(x)), and verify that the area under the curve y = f(x) xf'(x) from x = 0 to x = a is twice the area between the curve y = f(x) and the line ay = f(a)x. This result was used by Leibniz to illustrate the power of his infinitesimal methods.