# Question is crazy! Hopefully it doesn't come up in exam...any help?

• Aug 16th 2012, 07:31 AM
KayAB
Question is crazy! Hopefully it doesn't come up in exam...any help?
You are given the following two-point boundary value problem:

-(d/dx)(y*(e^x))+2y*(e^x)=(2-x)*(e^x), y(0)=y(1)=0

Simplify the equation and show that if the finite difference method is applied to the above problem, the resulting difference equation is:

-[(2-h)yi-1]+[4(1+h^2)yi]-[(2+h)yi+1]=2h^2(2-xi)
• Aug 16th 2012, 07:38 AM
HallsofIvy
Re: Question is crazy! Hopefully it doesn't come up in exam...any help?
Why "crazy"? It looks pretty close to "easy" to me. Once you have applied the product rule to \$\displaystyle d/dx(ye^x)\$ you can divide through by \$\displaystyle e^x\$ and the equation is very simple. I presume you know what a "finite difference method" is.
• Aug 16th 2012, 08:35 AM
KayAB
Re: Question is crazy! Hopefully it doesn't come up in exam...any help?
i'll give it a go
• Aug 16th 2012, 09:09 AM
KayAB
Re: Question is crazy! Hopefully it doesn't come up in exam...any help?
i get y-(2-x)=0