Hello,
yes, that did the trick, though I had to change the "from math import ~"
line to "import math". I also changed in line three the sqrt() function
to math.sqrt(). Otherwise there would be complaints:
<type 'exceptions.NameError'>: name 'sqrt' is not defined
WARNING: Failure executing file: <ex1.18.py>
The working code:
a = 2; b = 1; c = 2
import math
q = math.sqrt(math.fabs(b*b - 4*a*c))
x1 = (-b + q)/2*a
x2 = (-b - q)/2*a
print x1, x2
Thanks a lot!
David
Arun Tomar wrote:
hi!
On Sun, Nov 23, 2008 at 5:07 PM, David <[EMAIL PROTECTED]> wrote:
Hello everybody,
I recently came across a book by Prof. Langtangen: Indroduction to Computer
Programming: http://folk.uio.no/hpl/INF1100/INF1100-ebook-Aug08.pdf
I am trying to solve exercise 1.18 ("Why does the following program not work
correctly?"), but I don't find the mistake: why does the line
q = sqrt(b*b - 4*a*c)
problem here is that the method sqrt doesn't accepts -negative numbers
which in this case is the outcome of the expression above. to rectify
that u can use the following
q = sqrt(math.fabs(b*b - 4*a*c))
basically convert the negative number to absolute number, rest of the
stuff will work.
cause an error? I was playing around with the code, but got nowhere.
Here the entire code:
a = 2; b = 1; c = 2
from math import sqrt
q = sqrt(b*b - 4*a*c)
x1 = (-b + q)/2*a
x2 = (-b - q)/2*a
print x1, x2
Many thanks for a pointer!
David
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