4. The pressure p in a gas being compressed by a moving piston is measured at various positions x of the piston, where x is measured from the starting position

of the piston. The data are tabulated as follows: The total work done over this distance of 1 m by the piston is given by the integral A= p(x)dr, where A is the cross-sectional area of the piston. Compute this integral, taking A = 0.5 m²,