## [Bugs]ClassPad II OS Version 02.00.0000.0000

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**3**of**3**• 1, 2,**3**- SimonLothar
- Senior Member
**Posts:**596**Joined:**Sat Sep 15, 2012 6:59 am**Location:**Krautland ******Calculators:**Casio fx-7400GII, Casio fx-7400GII (SH4), Casio fx-9750 G II, Casio fx-9750 G II (SH4), Casio fx-9860G, Casio fx-9860 G SD, Casio fx-9860G Slim, Casio fx-9860 GII SD, Casio fx-9860 GII SD Power Graphic 2, Casio Classpad 330 plus, Casio fx-CG 20, Casio Classpad fx-cp400, Casio fx-CG 50

### Re: [Bugs]ClassPad II OS Version 02.00.0000.0000

The calculator uses the integration of SQRT(1/(1-X*X)) to calculate arcLen( SQRT(1-X*X)...) .

The problem seem to be the integration limits -1 and 1.

The expression 1/(1-X*X) is not defined for these values.

F. i. if you use -0.999... and 0.999... as integration limits, the calculation is at least possible.

The problem seem to be the integration limits -1 and 1.

The expression 1/(1-X*X) is not defined for these values.

F. i. if you use -0.999... and 0.999... as integration limits, the calculation is at least possible.

I'll be back!

- Wolfgang
- Junior Member
**Posts:**2**Joined:**Sat May 27, 2017 12:02 pm**Calculators:**Casio Classpad fx-cp400

### Re: [Bugs]ClassPad II OS Version 02.00.0000.0000

SimonLothar wrote:The calculator uses the integration of SQRT(1/(1-X*X)) to calculate arcLen( SQRT(1-X*X)...) .

The problem seem to be the integration limits -1 and 1.

The expression 1/(1-X*X) is not defined for these values.

F. i. if you use -0.999... and 0.999... as integration limits, the calculation is at least possible.

Thank you for the workaround but I wonder why ClassPad can't calculate the exact result?

I found out that when I slightly transform the result I get the correct answer:

So I think it's a bug in the ClassPad CAS and it would be great to get it fixed. Do you know how to report this to Casio?

Btw. Mathematica has no problem with both expressions and yields the same result:

Regards,

Wolfgang

- SimonLothar
- Senior Member
**Posts:**596**Joined:**Sat Sep 15, 2012 6:59 am**Location:**Krautland ******Calculators:**Casio fx-7400GII, Casio fx-7400GII (SH4), Casio fx-9750 G II, Casio fx-9750 G II (SH4), Casio fx-9860G, Casio fx-9860 G SD, Casio fx-9860G Slim, Casio fx-9860 GII SD, Casio fx-9860 GII SD Power Graphic 2, Casio Classpad 330 plus, Casio fx-CG 20, Casio Classpad fx-cp400, Casio fx-CG 50

### Re: [Bugs]ClassPad II OS Version 02.00.0000.0000

Yes, that is a bug indeed. They should correct it.

I'll be back!

### Re: [Bugs]ClassPad II OS Version 02.00.0000.0000

A new OS version has been released.

Version 2.01.2000

Calculation capability improvement

- PsySc0rpi0n
- Member
**Posts:**40**Joined:**Tue Dec 17, 2013 12:56 pm**Calculators:**Casio fx-9860 GII, Casio Classpad fx-cp400

### Re: [Bugs]ClassPad II OS Version 02.00.0000.0000

Is it only me or the integrals calculation is still very poor?

For instance, if I try to evaluate (250/(2*pi)) times the integral from pi/2 up to pi of sin(2*pi*50*t) dt, it tales like 3 of 4 minutes to return a result!

However, if I use 3.14 as an approximation for 'pi', the result is returned in like 6 or 7 seconds!

PS: I have just installed the latest OS update! I have told this in previous versions and I also tried to contact portuguese supporter and also some support email from asia that I can't remember, but never seen any improvements neither got any reply from that emai!

For instance, if I try to evaluate (250/(2*pi)) times the integral from pi/2 up to pi of sin(2*pi*50*t) dt, it tales like 3 of 4 minutes to return a result!

However, if I use 3.14 as an approximation for 'pi', the result is returned in like 6 or 7 seconds!

PS: I have just installed the latest OS update! I have told this in previous versions and I also tried to contact portuguese supporter and also some support email from asia that I can't remember, but never seen any improvements neither got any reply from that emai!

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