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Ocr mei c4 exercise 10a question 10

The graph shows the curve y=x^2 - 4
The region R is formed by the line y=12, the x-axis, the y-axis and the curve y=x^2 - 4 for positive values of x.

i) Copy the sketch graph and shade the region R.
Note: this part is fine.

The inside of the vase is formed by rotating the region R through 360' about the y-axis. Each unit of x and y represents 2 cm.

ii) Write down an expression for the volume of revolution of the region R about the y-axis
Note: This part is also fine. I came up with the integral of pi (y+4)dy with limits of 12 and 0 respectively.

iii) Find the capacity of the vase in litres.
This is the part I am having trouble with. I take into account that the increments of x and y are 2 cm, so I times my awnser by 4 at the end. The awnser at the back of the book is given as 3 litres which equals 3000cm_^3.

_{Any help on this would be much appreciated. Many thanks.}