MTH 2001: Project 2 Instructions • Each group must choose one problem to do, using material from chapter 14 in the textbook. • Write up a solution including explanations in complete sentences of each step and drawings or computer graphics if helpful. Cite any sources you use and mention how you made any diagrams. • Write at a level that will be comprehensible to someone who is mathematically competent, but may not have taken Calculus 3. Use calculus, but explain your method in simple terms. Your report should consist of 80−90% explanation and 10−20% equations. If you find yourself with more equations than words, then you do not have nearly enough explanation. See the checklist at the end of this document. • One person from each group must present the work orally to Naveed or Ali. Presenters must make an appointment. Visit the Calc 3 tab: http://www.fit.edu/mac/group_projects_presentations.php • Submit written work to the Canvas dropbox for Project 2 by October 7 at 9:55PM. The deadline for the oral presentation is October 7 at 2PM. Problems 1. You probably studied Newton’s method for approximating the roots of a function (i.e. approximating values of x such that f(x) = 0) in Calculus 1: (1) Guess the solution, xj (2) Find the tangent line of f at xj, y = f′(xj)(x−xj) + f(xj) (1) (3) Find the tangent line’s x-intercept, call it xj+1, 0 = f′(xj)(xj+1 −xj) + f(xj) xj+1f ′(xj) = xjf ′(xj) −f(xj) xj+1 = xj − f(xj) f′(xj) (2) (4) If f(xj+1) is sufficiently close to 0, stop, xj+1 is an approximate solution. Otherwise, return to step (2) with xj+1 as the guess. See this animation for a geometric view of the process. It simply follows the tangent line to the curve at a starting point to its x-intercept, and repeats with this new x value until we (hopefully) find a good approximation of the solution. Newton’s method can be generalized to two dimensions to approximate the points (x,y) where the surfaces z = f(x,y) and z = g(x,y) simultaneously touch the xy-plane. (In other words, it can approximate solutions to the system of equations f(x,y) = 0 and g(x,y) = 0.) Here, the method is http://www.fit.edu/mac/group_projects_presentations.php http://upload.wikimedia.org/wikipedia/commons/e/e0/NewtonIteration_Ani.gif (1) Guess the solution (xj,yj) (2) Find the tangent planes to each f and g at this point. z = f(x,y) = z = g(x,y) = (3) Find the line of intersection of the planes. (4) Find the line’s xy-intercept, call this point (xj+1,yj+1), xj+1 = yj+1 = (5) If f(xj+1,yj+1) < ε and g(xj+1,yj+1) < ε for some small number ε (error tolerance), stop, (xj+1,yj+1) is an approximate solution. Otherwise, return to step (2) with (xj+1,yj+1) as the guess. (a) Find equations of the tangent planes for step (2), an equation for their line of intersection for step (3), and find formulas for xj+1 and yj+1 for step (4). (b) What assumptions must we make about f and g in order for the method to work? How might the method fail? Explain in words h ...