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August 23, 2014

August 23, 2014

Posted by **Anna** on Tuesday, October 5, 2010 at 8:01pm.

18. All edges of a cube are expanding at a rate of 6 cm per second. How fast is the volume changing when each edge is a) 2 cm and b) 10 cm.

a)72 cm^3/sec b)1800 cm^3/sec

20. The formula for the volume of a cone is v=(1/3)(pi)(r^2)h. Find the rates of change of the volume if dr/dt is 2 in per min and h=3r when a) r=6 in and b)r=24 in

a)216(pi) in^2/min

b)12864(pi) in^2/sec

thanks

- calculus -
**Reiny**, Tuesday, October 5, 2010 at 8:17pm18. correct

20 a) correct

b) I got 3456π inches^2/min (why have you got in^2/sec ? )

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