# Help...Linear Approximation..

• May 12th 2009, 08:04 PM
Raidan
Help...Linear Approximation..
Approximations: A circular cylindrical tank,
V=
πr^2h of internal radius 12m and height 20m is to be painted on the inside: top,bottom and sides,with paint of thickness 0.05cm.

Use the linear approximation of
V to calculate how many litres of paint (1 litre=1000cm^3) are required?(Wondering)

convert all units to cm
• May 13th 2009, 06:18 AM
HallsofIvy
Quote:

Originally Posted by Raidan
Approximations: A circular cylindrical tank,
V=
πr^2h of internal radius 12m and height 20m is to be painted on the inside: top,bottom and sides,with paint of thickness 0.05cm.

Use the linear approximation of
V to calculate how many litres of paint (1 litre=1000cm^3) are required?(Wondering)

convert all units to cm

$V= \pi r^2 h$ so $dV= 2\pi r hdr+ \pi r^2 dh$
Here, dr and dh are the thickness of the paint, 0.05 cm.