The Museum of HP Calculators

HP Forum Archive 21

 desolve exampleMessage #1 Posted by Richard Berler on 20 Oct 2013, 10:30 p.m. I can't figure out how to execute desolve on an example from the NSpire desolve entry in their refernce guide. The example is: deSolve(y''-2*y'/x+(9+2/x^2)*y=x*e^x and y(pi/6)=0 and y(pi/3)=0,x,y) I used the y'' example as a template from the onboard help. I get empty brackets in CAS and syntax error in home.

 Re: desolve exampleMessage #2 Posted by Les Koller on 21 Oct 2013, 2:42 a.m.,in response to message #1 by Richard Berler The nSpire CAS reference I downloaded has a similar problem on page 36 at the top. The function of x associated with w (this example uses w as the variable instead of y?)is given as a fraction with denominator x, but NO NUMERATOR. This is what causes the error with that example. When I type your example verbatim in to my nSpire calculator page, it returns y= e^pi/3 * x * cos(3x) - e^pi/6 * x * sin(3x) + x*e^x, all of that over 10. It is VERY similar to the result given in the reference manual I have. I played with it for a while to see what numerator would give the answer in the manual, but gave up after an hour. If you figure it out, clue me in huh? It has been almost 30 years since my last Dif Eq class :(

 Re: desolve exampleMessage #3 Posted by Richard Berler on 21 Oct 2013, 11:09 a.m.,in response to message #2 by Les Koller Yes, that's the example...they used "w"...I used "y" to make it more simple to key in on the Prime. My question is, how do I execute this on the Prime, and get the answer (or an equivalent) as given on the NSpire? My attempt in CAS produced empty brackets.

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