Eulers' Method+General solution of ordinary differential eq!

blokey2

New member
Joined
Jan 10, 2010
Messages
1
Hi. I need some help with some questions that we are required to do as coursework. I've tried very hard to find the methods for these but unfortunately many of them aren't clear to me, I'm at a dead end and I hope I can get some help here. I'd appreciate it much. I know the sticky says to post any workings I have attempted but honestly I'm at a complete loss here, I'm embarrassed to admit :(

The problems involve Euler method, Modified Euler method and finding the general solution of an ordinary differential equation.

I will post the questions here but I don't want just the solutions... it would help me a lot if you could perhaps talk me through the workings out. Thanks!

Q1) Solve the equation (dv/dt)=t+(v/t), subject to v(1) = 1, to find v(2) working to 5 significant figure accuracy throughout and using:

(a) Euler’s Method with step lengths h = 0.5, and h=0.25.

(b) The Modified Euler Method with step lengths h = 0.5 and h = 0.25.

(c) Given that the actual value of v(2) is 4m/s^2 calculate the absolute values of the errors in your results for parts (a) and (b). What happens to the size of the error for Euler’s Method when the value of h is halved? What happens to the size of the error for the Modified Euler Method when the value of h is halved?

(Please note that for these methods there is no difference between dv/dt=f(t,v) and dy/dx=f(x,y) .)

Q2) Find the general solution of the ordinary differential equation (dy/dx)+xy=x

and find the solution, y(x), that satisfies y(0)=-1.

Q3) Find the general solution of the ordinary differential equation (d^2y/dx^2)+4y=cos2x
 
Euler is simple, in this context.

1) Start where they tell you to start.
2) Find the equation of the tangent line where you started.
3) Follow the tangent line as far as the step size indicates.

That's it. Do that over and over, with each new point being the new starting place, until you get to where you need to stop.

Show us this one and we can talk about "modified".
 
Top