# Cp 300 Is Not Able To Solve This Differential Equation

### #1

Posted 14 May 2007 - 06:15 PM

my cp shall solve this d-equation:

y'*(x+1)+x*(y-1)=0

the result from the cp is: y'(x+1)=xy+y , what's that ?

mmmh...

the right solution is: y= ((x+1)*C1) / (e^(x)) + 1

(TI-89 is able to solve this)

bug ?

### #2

Posted 14 May 2007 - 07:21 PM

It show me {y=x.e^(-x).const(1)+e^(-x).const(1)+1}

CP can do it, maybe you can match with the CP300.

Please don`t compared the casio with the texas or another calculator.

If you don`t know how to uses something on the CP300 just ask, don`t say because the ....... can do it.

### #4

Posted 14 May 2007 - 09:32 PM

### #5

Posted 15 May 2007 - 12:20 AM

I'm not quite sure why it isn't working. it works fine on my ClassPad both in real and complex modes. Your screen capture doesn't show the full argument list. What is the full command line? Not that this should effect the result, but do you have anything stored in 'x' or 'y'?tell me how to calculate this equation in cp...

here is a screenshot, i have took it from cp-manager 2.20.

but i have the same result on my cp mit ver.3.01:

???

Interesting, it looks like you need an explicit * after y'.I'm not quite sure why it isn't working. it works fine on my ClassPad both in real and complex modes. Your screen capture doesn't show the full argument list. What is the full command line? Not that this should effect the result, but do you have anything stored in 'x' or 'y'?

### #7

Posted 15 May 2007 - 02:36 PM

Hmm, I'm not surprised too much. y(x+1) doesn't need the explicit * because y (in bold italics) is designed just for that (a "stand-alone" variable). However, y'(x+1) does need to be written as y'*(x+1) because y is followed by an operator, and y' is not treated as a "stand-alone" variable. I personally never use bold italics variable names; of course, they are easier to type (especially for x, y, and z), but they look ugly to me and they have problems such as this one.hmm, yes, the CP needs an explicit * after y' . Now, i see the right solution... very strange

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