4-) A thin sheet of metal is cut into the shape as shown where it has 3 straight edges and one curved edge modeled by f (x) = L 1+x' The density of this sheet metal is given by 90:) = x2 grmfcmz. x) a) Give an expression for the mass of one representative slice of the sheet metaL Note that the problem is asking for mass. not area. [2 pts) [1) Write a Left Riemann Sum with [1:5 that approximates the total mass of the sheet metal. Do not evaluate it [2 pts) c) Give an integral that gives the exact value of the total mass of the sheet metal. Do not evaluate. (1 pt)