Question

Help! Integration question where to start? 'A contractor digs roughly cylindrical wells to a depth of h metres. He estimates that the cost of digging at the depth x metres is: (1/2*x^2 + 4) dollars per m^3 of earth and rock extracted. If a well is to have a radius r metres, show that the total cost of digging a well is given by: C(h) = pi*r^2*((H^3+24H)/6) + C0 dollars. Hint: dC/dx = dC/dv * dV/dx

Answer 1

cool problem.

Answer 2

have you tried anything yet?

Answer 3

well i got that V = pi*r^2*x for the top half of the cylinder, so dV/dX is pi*r^2