+3 votes
in Class 12 by kratos

The volume of a right circular cone of radius r and height h is given by V = 1 /3 πr 2 h. Suppose that the height decreases from 20cm to 19.95cm and the radius increases from 4cm to 4.05cm. Compare the change in volume of the cone with the estimate given by the linear approximation.

1 Answer

+2 votes
by kratos
 
Best answer

Write V(r, h) for the volume of the cone to emphasize that it is a function of both radius r and height h. The volume of the old cone is V(20, 4) = 1675.52cm3 and the volume of the new cone is V(19.95, 4.05) = 1687.99cm3 . The change of volume is thus

Therefore the approximate volume of the new cone is

l(19.95, 4.05) = 1675.52 − 167.55 · 0.05 + 418.88 · 0.05 = 1688.09 .

The approximate change of volume is thus

l(19.95, 4.05) − V(20, 4) = 12.57 .

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