Can you help me to solve these 2 questions? They are very confusing and I cannot find the right way.
I have the answer from the book but I need the way to solve it.
Thanks a lot!!!!
1) A cylindrical hole of diameter 2 cm is bored through a sphere of radius 4 cm. The hole has been bored so that its main axis passes through the centre of the sphere. Calculate the volume of the remainder of the sphere.
2) Consider that part of the parabola y = (x-1)*(x+2) which lies below the x-axis. Calculate the volume of the solid formed when this part is rotated about the line y =4.