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Francesco999
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Differential equation

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Hp Prime Graphing calcultor

Hello, 

I' m tryng ti solve this differential equation in CAS using my Hp Prime Graphing calcultor: 

desolve(y'=1.2*e^(-0.3*x) -0.00672*y^2,x,y), but the calculator doesn' t give me amy result: [].

Where did I go wrong?

Thanks for the attention

3 REPLIES 3
Joe_Horn
Level 8
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If your CAS expression is typed with just ",x" at the end instead of ",x,y" a result is obtained. Is it the result you're looking for?

 

Also, please note that CAS is intended for exact and/or symbolic math, not decimal number approximations, which is what Home view is used for.  Entering a decimal point anywhere in a CAS expression forces it to revert to approximate mode.  If you want to use the full power of CAS, never include any decimal points anywhere in the inputs.  If you type your expression in CAS using exact values (e.g. instead of -0.3 use -3/10), CAS will return an exact result instead of a decimal approximation.

 

Disclaimer: I don't work for HP. I just enjoy using their calculators.

-Joe-
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Jurjen_NE
Level 3
28 26 1 5
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The solution of this differential equation involves a Bessel function. The Bessel functions are not in the CAS, so the calculator had no way of expressing the answer.

Jurjen Bos
Calculator nerd since 1980. Cryptographer by profession.
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Jurjen_NE
Level 3
28 26 1 5
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Of course, if it is a numerical value you're after, you can use odesolve.

Jurjen Bos
Calculator nerd since 1980. Cryptographer by profession.
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