138
Chapter 6
•
Additional Topics
§6.2
programming language
3
(chosen here for simplicity) the
decimal
module can be used to set
any level of precision.
4
Below we show how to get accuracy up to 50 decimal places using
Heron’s formula for the triangle in Example 2.16 from Section 2.4, by using the python
interactive command shell:
[1]: from decimal import
*
[2]: getcontext().prec = 50
[3]: a = Decimal("1000000")
[4]: b = Decimal("999999.9999979")
[5]: c = Decimal("0.0000029")
[6]: s = (a+b+c)/2
[7]: K = s
*
(sa)
*
(sb)
*
(sc)
[8]: print Decimal(K).sqrt()
0.99999999999894999999999894874999999889618749999829
(Note: The bracketed line numbers are just command prompts, not part of the code.)
Notice in this case that we do get the correct answer; the high level of precision eliminates
the rounding errors shown by many calculators when using Heron’s formula.
Another software option is Sage
5
, a powerful and free opensource mathematics package
based on Python. It can be run on your own computer, but it can also be run through a web
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This note was uploaded on 01/21/2012 for the course MAC 1130 taught by Professor Dr.cheun during the Fall '11 term at FSU.
 Fall '11
 Dr.Cheun
 Calculus, Addition

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