Re: [Matplotlib-users] Question?

[Benjamin R. <ben...@ou...>]

I think I found your errors.

First, you are correct, the scientific notation in python is as you
understand, there is nothing wrong with that.

Instead, you have a problem with order of operations.  In the last quantity,
you have "((x**2)/4*(1e4**2)*(3e14**2))"
According to the equation that you wrote out in the attached image, you
need: "((x**2)/*(*4*(*2*e4**2)*(3e14**2))*)*"
Note that you needed parentheses for the entire denominator.  Also, the
1e4**2 should have been 2e4**2.

This gives me values between 4.3125e-48 and 5.5359e-48.

Ben Root

On Tue, Jun 8, 2010 at 12:47 PM, Waléria Antunes David <
wal...@gm...> wrote:

> I understand what you are saying, but my functions are these, attached.
>
>
> Scientific notation in Python is not so?
>
> *Math *              *Python*
>
>
> Pinc = 10-6      Pinc = 1e-6
>
> 3,0x1014        3e14
>
>
> ?
>
>
> Then, changing my functions of the images attached for python is as bellow:
>
>
> y1 = -108*(x**2)/(3e14**2)
>
> y2 = 1*((1.38e-23*(1e0+4)/1e-6)*((x**2)/4*(1e4**2)*(3e14**2))))
>
> Is not it?
>
>
>
>
>
>
> On Tue, Jun 8, 2010 at 1:34 PM, Gökhan Sever <gok...@gm...>wrote:
>
>>
>>
>> On Tue, Jun 8, 2010 at 10:19 AM, Waléria Antunes David <
>> wal...@gm...> wrote:
>>
>>>  Hello!!!
>>>
>>> My name is Waleria. I work at INPE in Sao Jose dos Campos, Brazil. And
>>> I'd like to make a question. I'm in trouble to generate a two functions
>>> graph.
>>>
>>> I have a problem to generate a graph of the two functions. I have this
>>> functions, is bellow:
>>>
>>> *y1 = -108*(x**2)/(3e14**2)*
>>>
>>> *y2 = 1*((1.38e-23*(1e0+4)/1e-6)*((x**2)/4*(1e4**2)*(3e14**2))))*
>>>
>>>
>>> You might need to check your y2. You are mixing integers and floats which
>> possible have resulted with some rounding errors. I get e+30 when I assert
>> the terms as floats in y2.
>>
>> For the plotting: y1 is around -e-20 whereas y2 goes up to e+30. You can't
>> see the trend easily on one axes even if you could scale
>> them logarithmically (hint logarithm is only defined for positive numbers).
>> You can make a positive assumption for the y1 and plot them on one y-axes
>>
>> yscale('log')
>> axis(ymin=1e+20, ymax=1e+30)
>>
>> Still this won't let you see the functions trends that you are looking to
>> see.  I would suggest you to use multipe figures or investing a bit more
>> time to use parasite axes example of JJ.
>>
>>
>>
>>
>> --
>> Gökhan
>>
>
>
>
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