a mass point (mass m) is moving in the x-y plane. there are no external forces present, but the mass is tethered to the origin () by a string of fixed length r. this constraint can be expressed by re- quiring that the finction géer)-0, where gxy)-xr. using lagrangian multipliers, write down the euler-lagrange equations of motion for the variables x and y. a solution can be found by making the ansatz x-kcosφ andys rsmp for some parameter φ(1) (of course we know what that is. but the point is that we're not supposed to start out with φ as generalized coordinate, but only use it at this point). obviously, this solution "automatically" fulfills the constraint. show that you can now solve the set of two equations for x and y both for φ(t) and for the lagrangian multiplier. from your solution. extrac t the x- and y-components of the force of constraint exerted by the string on the mass point.