There are two different points on the curve with the {{MATH_100}}coordinate {{MATH_101}}. The advantage of the expression for {{MATH_102}} that we obtained above is that it can be used for computation of the slope of the tangent line at each of these two points, and at any other point on the curve, where defined. So, for the second part of the problem, we simply plug {{MATH_103}} and {{MATH_104}} into the expression above, hence the slope of the tangent line at this point is {{MATH_105}}. For the third part of the problem, we simply plug {{MATH_106}} and {{MATH_107}} into the expression above, hence the slope of the tangent line at this point is {{MATH_108}}.