(15 points) Suppose the charge density on an annular (1≤r≤2) semi-circular plate (shown below) is given by the linear function σ(x, y) = 3+x+y. Find the total charge by evaluating the integral ∬Dσ(x, y)dA where D is the shaded region below given by D = {(x, y):1≤x2+y2≤4, x≤0}. (Hint: Write this integral in polar coordinates and evaluate it. )