81 What is the volume of the solid of revolution O obtained by rotating the region bounded by 15 47 1 y = 2x' + 1, x =1, and x = 0 around the O 5 r-axis? 47 1 O 15 O 15 9) What is the volume of the solid of O -7 units revolution generated by rotating the O 0 units area bounded by y = vcosa, the O 1 units T-axis, c = 0, and x = 1/2 around the O 7 units r-axis