I do not know much of anything about sage. But I was using desolve on 
http://www.sagenb.org to compare an answer, 
and I am confused on the type-setting of of constant of integration in 
solution of an ode. 

Googled around but nothing specific I could find.

When I ask sage to solve an ode using desolve, it seems to use `c` for 
constant of integration in the result, like this:

reset()
x= var('x')
y = function('y', x)
desolve(diff(y,x)+y, y,ivar=x)

which gives

c*e^(-x)

I wish it generated at least uppercase `C` or such. But any way. Now the 
confusing part. 

If I use `c` myself in the ode, then the result will contains 2 c's. The 
constant of integration `c` that sage uses, and my own `c` which I have in 
the ode itself. So how is a user to know which is which when they look at 
the result??

reset()
x,c= var('x c')
y = function('y', x)
desolve(diff(y,x)+c*y, y,ivar=x)


which gives

c*e^(-c*x)

Is there a way to tell sage to use at least upper case letter for constant of 
integration? 

This is how Mathematica does it:

In[67]:= DSolve[y'[x]+c*y[x]==0,y[x],x]
Out[67]= {{y[x]->E^(-c x) C[1]}}


You can see it is easy to see which is the constant of integration in the 
result. If there are
more than one constant of integrations, they become C[1], C[2], etc....

same with Maple

dsolve(diff(y(x),x)+c*y(x)=0);
 y(x) = _C1 exp(-c x)


see, it uses _C1

How can one make sage change this behavior so it is easier to read the results? 
lower case
letters for constant of integrations is not really a good way to do this.

thanks,



-- 
To post to this group, send email to sage-support@googlegroups.com
To unsubscribe from this group, send email to 
sage-support+unsubscr...@googlegroups.com
For more options, visit this group at 
http://groups.google.com/group/sage-support
URL: http://www.sagemath.org

Reply via email to