eulers method with excel...

• May 14th 2011, 10:55 AM
slapmaxwell1
eulers method with excel...
ok i have to do a bunch of problems on excel using Euler's method, modified Euler's and fourth order Runge kutta method? i was wondering if anyone knew of a good tutorial.

thanks
• May 18th 2011, 11:24 PM
CaptainBlack
Quote:

Originally Posted by slapmaxwell1
ok i have to do a bunch of problems on excel using Euler's method, modified Euler's and fourth order Runge kutta method? i was wondering if anyone knew of a good tutorial.

thanks

This hardly needs a tutorial does it? You need one row per epoc, the first row containing the initial conditions. The first column should contain the times corresponding to the epocs, there should be a named variable containing the nominal step size h.There should be columns for the derivatives and estimates at the computationall nodes to give in the last column the estimate of the solution at the time corresponding to the epoc.

CB
• May 19th 2011, 02:19 AM
slapmaxwell1
it probably doesnt, i was just having a hard time getting excel to back up what i was doing on paper. i solved the differential equation using bernouli, but as i went from euler's method to runge kutta my numbers were getting worse. ok so my equation was y'=2y-y^2.

using bernouli or even separation of variables, i found....

http://latex.codecogs.com/gif.latex?...2x}}{e^{2x}+4}

so Y(1) was approximately 1.29757....

euler method was ok, i found Y(1) was 1.27 something....

my problem came when i tried using improved euler and runge kutta
• May 19th 2011, 03:25 AM
CaptainBlack
Quote:

Originally Posted by slapmaxwell1
it probably doesnt, i was just having a hard time getting excel to back up what i was doing on paper. i solved the differential equation using bernouli, but as i went from euler's method to runge kutta my numbers were getting worse. ok so my equation was y'=2y-y^2.

using bernouli or even separation of variables, i found....

http://latex.codecogs.com/gif.latex?...2x}}{e^{2x}+4}

so Y(1) was approximately 1.29757....

euler method was ok, i found Y(1) was 1.27 something....

my problem came when i tried using improved euler and runge kutta

This is fairly simple to do, and to demonstrate face to face, but over a text interface almost impossible, have you tried searching on youTube for a demo/tutorial?

I have checked what you call improved Euler and with a time step of 0.1, and initial condition f(0)=2/5 get f(1)~=1.285 (see attachment).

CB
• May 19th 2011, 04:42 AM
slapmaxwell1
Quote:

Originally Posted by CaptainBlack
This is fairly simple to do, and to demonstrate face to face, but over a text interface almost impossible, have you tried searching on youTube for a demo/tutorial?

I have checked what you call improved Euler and with a time step of 0.1, and initial condition f(0)=2/5 get f(1)~=1.285 (see attachment).

CB

i haven't checked you tube, but i will take a look at it as well as the attachment.