[sf-lug] [PYCLASS] Still on exercise 2.1

[jim]

   (hint) read the section in the chapter about 
integer division compared with floating point 
division. the way you express the operands 
(numbers) makes a difference. 


On Fri, 2008-10-03 at 20:17 -0700, Christian Einfeldt wrote:
> hi, 
> 
> Okay, with Jim's help, I was able to get past exercise 2.2.  Now I am
> on exercise 2.4.1, which poses this question:
> 
> The volume of a sphere with radius R is 4/3piRcubed.  What is the
> volume of a sphere with radius 5?
> 
> I have been vexed by this problem.  As the problem is written, I am
> interpretting it to ask me to first divide 4 by 3.  Then, I am asked
> to multiple the product of that figure by piRcubed.  We are told that
> the answer is _not_ 392.6, but that is the only answer that I seem to
> be able to produce.  Any thoughts?  My results are below:
> 
> >>> (4/3)*(pi*5**3)
> 392.69874999999996
> >>> (4/3)*pi*(5**3)
> 392.69874999999996
> >>> (4/3)*(pi*(5**3))
> 392.69874999999996
> >>> ((4/3)*pi)*(5**3)
> 392.69874999999996
> >>> 
>