On Mar 30, 10:31 am, Jason Grout <jason-s...@creativetrax.com> wrote:
> On 03/30/2010 08:31 AM, Jared Schlieper wrote:
>
>
>
> > Greetings,
>
> > I am in the process of converting calculus 3 assignments from
> > Mathematica to Sage and came upon an error I can't figure out.
>
> > Trying to find the mass of a region bounded by two functions(g1,g2)
> > with a given density. Below is the code,
>
> > x, y = var('x ,y')
> > density=e^(sqrt(x))+e^(y^2/2)
> > g1=e^(2*x)-1
> > g2=5-5*(x-1)^2
> > p=plot(g1,0,1)
> > p+=plot(g2,0,1,color='red')
> > show(p)
> > b=(g2-g1).find_root(.7,1.0,x)
> > a=(g2-g1).find_root(-.1,.2,x)
> > f=integral(density,y,g1,g2)
> > numerical_integral(f, a, b)
>
> > This results in a TypeError: float() argument must be a string or a
> > number
>
> > I have tried various changes and still the same error. My thought is
> > the error is due the error function that results from the first
> > integration. Am I missing something?
>
> Nope, it's a bug. The problem is that Sage tries to automatically
> compile f into a version that is fast to evaluate, but does not handle
> complex numbers. You have complex numbers in f, so it fails.
>
> Apparently f.nintegral does not try to compile f into a fast version,
> but uses Maxima to do the numerical integration.
>
> Do you mind sharing your worksheets? I am teaching calc 3 this semester
> and next semester as well, and I'd be interested in seeing them.
>
Thanks for the reply.
I don't mind sharing but the worksheets need some tweaking. I will try
to clean them up and make public on sagenb.( Might not be until the
weekend though.)
Jared
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