The toughness of a material is technically defined as the plastic strain energy absorbed by the material (the olive region in the figure below). Practically speaking, it's a measure of how much deformation a material can undergo (or energy it can absorb) before failure.
Write a function to calculate the toughness of a material—the absorbed strain energy minus the resilience. This can be accomplished by combining the code written in problem 2 (resilience) and problem 6 (absorbed strain energy). Also, return the fraction of absorbed strain energy that the toughness represents.