A Ductile metal wire of uniform cross-section is loaded in tension until it just begins to neck the curve of true stress vs true strain for this wire approximates to o=420e^0.33 MPa a. Assuming that the volume is conversed, derive a differential equation relating the true stress to the true strain at the point of necking. b. Estimate the ultimate tensile strength of the metal and the work required to take 1m^3 of the wire to the neck.