[HP50G] DESOLVE Error: Bad Argument Type

01292021, 01:50 AM
Post: #1




[HP50G] DESOLVE Error: Bad Argument Type
I'm trying to solve a differential equation with DESOLVE, but I get bad argument type error message. Numeric, Approx and Complex CAS flags are disabled (actually I disabled all CAS flags).
Here is what I enter on RPN mode: 1. [ 'd1d1y(t)+5*y(t)=2*COS(t/2)' 'y(0)=6/5' 'd1y(0)=1/2'] + ENTER 2. 'y(t)' 3. DESOLVE (LEFT SHIFT + 4[CALC] + F3[DIFF] + F1[DESOL]) Note: I'm using soft menus (flag 117 set). Does anybody have any clue why I'm getting the error? 

01302021, 12:38 PM
Post: #2




RE: [HP50G] DESOLVE Error: Bad Argument Type
Hello dns.olic,
I keyed in: 1. 'd1d1y(t)=2*COS(t/2)5*y(t)' 2. 'y(t)' And use DESOLVE and I get a result with the two constants cC0 and cC1. If I key in 'd1d1y(t)+5*y(t)=2*COS(t/2)' and not 'd1d1y(t)=2*COS(t/2)5*y(t)', I although get an error message. Same procedure with constrains, same behavior DESOLVE works with: [ 'd1d1y(t)=2*COS(t/2)5*y(t)' 'y(0)=6/5' 'd1y(0)=1/2'] + ENTER 2. 'y(t)' 

01312021, 10:06 AM
Post: #3




RE: [HP50G] DESOLVE Error: Bad Argument Type
Hello,
it may be useful to read this tutorial: Using Desolve https://www.hpcalc.org/details/7291 https://www.hpcalc.org/hp49/docs/misc/usingdesolve.pdf regards Simone 

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