A tank in the form of an inverted right circular cone is 8m across the top and 10m deep. If the tank is filled to a height of 9m with water, find the work done in pumping the water to the top of the tank:

the radius is 4, the depth is 10

so

the coordinates of the line passes through

(4,0) and (0,-10)

Equation of the line is: (y-(-10)) = 5/2(x - 0)

x = 2/5y + 4

work is :

$\displaystyle d(W) = 9180\pi(\frac{2}{5}y + 4)^2ydy$

and multiplied by y is the change in length to the top of the cone right?

is the math model correct?

$\displaystyle 9180\pi \int_{-9}^{-1} (\frac{2}{5}y + 4)^2 ydy$

thank you so much