174 replies to this topic

[T.U]

When I tried ∑(diff(sin(x),x,n),n,1,3), I got Domain Error.
Is it bug?

[sanjuanino]

hello everyone, try to perform this:

fourier(sin(x)/abs(sin(x)),x,w)

after that i got stack error, then click ok and touch "main" or "menu" with the stylus.

You will get an error that causes the classpad to be restarted.

Classpad OS 3.06.1000

Greetings!

[helder7]

@sanjuanino, my classpad only freeze with your equation.

[Cartix]

Classpad OS 3.06.1000

Isn't this Classpad 330+ ?

[helder7]

Isn't this Classpad 330+ ?

No, 330+ is 3.10.xxxx

[sanjuanino]

@sanjuanino, my classpad only freeze with your equation.

Hello helder7. My classpad 300 freeze too until you get "stack error". Let me show you some pics:

FIRST I INPUT THE EQUATION...




THEN I PRESS "EXE" AND WAIT UNTIL YOU GET THIS ERROR:




FINALLY GO TO MENU USING THE STYLUS...

[PsySc0rpi0n]

I've recentrly updated my fx-CP400 to the latest version available 02.00.0000.0000.

I've just noticed an unwanted behavior.

When trying to save a new file in eActivity application, the calculator freezes and I'm forced to remove batteries to have the calculator back.

Another bug is that sometimes when we want to select any character, symbol or whatever from the soft keyboard using the stylus pen, instead of the selected character/symbol or whatever appears, it appears the last character used before the actual one. I mean, for instance if I use the fraction symbol and then try to use round brackets on the upper side of the fraction, it appears another fraction instead of the brackets!!!

[MicroPro]

Thanks for reporting, I would try to contact CASIO support to let them know (although the way they answer might now show their appreciation for you reporting bugs )

 

 

When trying to save a new file in eActivity application, the calculator freezes and I'm forced to remove batteries to have the calculator back.

 

Doesn't CP-II have a "P" or "Reset" button at its back to push instead of pulling out the batteries?

[PsySc0rpi0n]

Thanks for reporting, I would try to contact CASIO support to let them know (although the way they answer might now show their appreciation for you reporting bugs )

 

 

 

Doesn't CP-II have a "P" or "Reset" button at its back to push instead of pulling out the batteries?

 

 

Ahh yes... In fact it has the reset button.. Didn't remember to check before taking the batteries out!

[MicroPro]

Ok.

 

btw to clear any confusions: the "I would try" in the post above didn't mean that literally "I" will try (don't own a CP400 anyway); I meant you try to contact support for those.

[PsySc0rpi0n]

Sir MicroPro, the bug is now solved and a new OS version is already available in edu.casio site!!!

Edited by PsySc0rpi0n, 21 September 2014 - 11:02 AM.

[PsySc0rpi0n]

Hi everyone...

 

I think a new bug was found. I already asked to one representative in my country to report this problem to Germany and also to Tokyo which she already did and got an answer (from Germany). They have made some tests and said that they were reporting it to Tokyo.

 

The issue is that the calculator takes an absurd amount of time to calculate integrals if the Pi symbol is used. If the Pi symbol is replaced by an approximate value of 3.141, the result comes out fast.

 

I'll be in touch when I get news!

[quinyu]

I have experimented with a number of indefinite integrals, some of which I have found problematic. I am using a CP II (not emulator), 02.00.4000.0000. I will not list any errors related to absolute values.

 

Int(1/(4-cos(x)²),x): Should come out as x/(2sqrt(3))+1/(2sqrt(3))*atan(cos(x)sin(x)/(3+2sqrt(3)+sin(x)²). Instead, I'm receiving 1/(2sqrt(3))*atan(2sqrt(3)/3*tan(x)). This is only true for a small zone.

Int(tan(x)tan(x-a),x): Unable to solve.

Int(x²/(x⁶-6x³+13),x): The expected output is -1/6*atan((3-x³)/2). The CP II returns ln(x⁶-6x³+13)/18 after simplification, which is clearly not correct.

Int(1/(x*sqrt(x²-a²)),x): expected: 1/a*atan(sqrt(x²-a²)/a). CP II returns (ln|x|-ln|2a²/sqrt(-a²)-2sqrt(x²-a²))/sqrt(-a²). Incorrect, and even more so due to the negative values below the square roots.

Int((1-tan(x)/sin(2x),x); Int((a²-4cos(x)²)^3/4*sin(2x),x); Int(1/sqrt(a^2x-1),x); Int(a^xcos(x),x); Int(asin(x)/x²,x); Int(asin(x)²,x); Int(acos(sqrt(x/(x+1))),x); Int(a+bx^k)ⁿx^k-1,x): simply cannot solve them.

Int(1/(x^m(a⁴-x⁴)),x) apparently hangs the calculator. I gave it some time to work it out. No win. Granted it's a difficult one, but should just tell that it cannot solve it.

Int(x/(a⁴+x⁴),x); Int(x²/(a⁴+x⁴),x): negative values under square roots, whereas the expression would need no such complexes. And in fact complex was disabled. Enabling it saves the first but not the second.

Int(1/(a⁵+x⁵),x); Int(x/(a⁵+x⁵),x); Int(x²/(a⁵+x⁵),x); Int(x³/(a⁵+x⁵),x); Int(1/(x(a⁵+x⁵)),x): doesn't do them.

Int((x⁴+1)/(x⁶+1),x): "Error: Non-Real in Calc" Granted, it's not easy, but it should be doable...

Int((x^n-1-1)/(xⁿ-nx),x) doesn't get solved. Expected is ln(xⁿ-nx)/n

Int(1/(x²(a⁴+x⁴)³),x): many stacked negative roots, whereas it's not needed. -(32a⁸+81a⁴x⁴+45x⁸)/(32a¹²x(a⁴+x⁴)²)-45/(128a¹³sqrt(2))*(ln((a²-ax*sqrt(2)+x²)/(a²+ax*sqrt(2)+x²))+2tan^-1((ax*sqrt(2))/(a²-x²))) is such a solution.

Int(1/(x³(a⁴+x⁴)³),x): many negative square roots again. -(8a⁸+25a⁴x⁴+15x⁸)/(16a¹²x²(a⁴+x⁴)²)-15/(16a¹⁴)tan^-1(x²/a²) would avoid all of them.

Int(x⁶/((2x⁵+3)²),x) isn't evaluated. The integral is nasty but exists.

Int(x¹³/(a⁴+x⁴)⁵,x) in real mode gives negative square roots unnecessarily (weirdly enough, in complex mode the result is fine.) A result without those would be x²(15x¹²-73a⁴x⁸-55a⁸x⁴-15a¹²)/(768a⁴(x⁴+a⁴)⁴)+5/(256a⁶)*tan^-1(x²/a²)

Int(sqrt(x³)*(x²+1)*(2sqrt(x)-x)²,x): the output is correct but very chunky and it refuses to merge the powers even with simplify.

Int((x^3/2-3*x^3/5)²(4*x^3/2-1/3*x^2/3),x): output is correct but powers are not merged even on simplify.

Int((1+x^1/4)^1/3/sqrt(x),x): doesn't evaluate it, regardless of being in real or complex mode. Expected answer is 3/7*(1+x^1/4)^4/3(4*x^1/4-3). This integral, with the most common strategy, needs double substitution.

Int(1/(x³*sqrt((x+1)³)),x): doesn't evaluate it regardless of mode. Expected answer is (15x²+5x-2)/(4x²*sqrt(x+1))+15/8*ln((sqrt(x+1)-1)/(sqrt(x+1)+1)), this last term of course can also be written as -15/4*arctanh(sqrt(x+1)) based on the identities of the inverse hyperbolic tangent.

Int(1/(x⁵*sqrt((1-x)⁷)),x): doesn't evaluate it regardless of mode. Expected answer is (3249*(1-x)^3/2-10224*(1-x)+10769*sqrt(1-x)-3800)/(384*(sqrt(1-x)-1)⁴)+(3249*(1-x)^3/2+10224*(1-x)+10769*sqrt(1-x)+3800)/(384*(sqrt(1-x)+1)⁴)+(450*(1-x)²+50*(1-x)+6)/(15*(1-x)^5/2)-3003/128*ln((sqrt(1-x)+1)/(sqrt(1-x)-1)); the last term can also be written as -3003/64*arctanh(sqrt(1-x)) based on the identities of the inverse hyperbolic tangent.

Int(1/(x⁵*((x-1)²)^1/3),x): doesn't get evaluated. Expected answer is (x-1)^1/3(1/(4x⁴)+11/(36x³)+11/(27x²)+55/(81x))+55/81*ln(((x-1)^1/3+1)/x^1/3)+110sqrt(3)/243*arctan((2(x-1)^1/3-1)/sqrt(3))

Int(sqrt(x-5)sqrt(x+3)/((x+1)(x²-25)),x): doesn't get evaluated. Expected answer is 1/3*arctan(sqrt((x-5)/(x+3)))+1/(3sqrt(5))*arctanh(sqrt(5(x+3))/(x-5))

Int(x²*(1-x²)^1/4*sqrt(1+x)/(sqrt(1-x)*(sqrt(1-x)-sqrt(1+x))),x): The calculator reports "error: insufficient memory." It is true that this is a rather complicated one, and the Nspire CX CAS, the HP 50G or HP Prime cannot solve it either.

Int(x*(1+x)^2/3*sqrt(1-x)/(sqrt(1+x)*(1-x)^2/3-(1+x)^1/3*(1-x)^5/6),x): doesn't get evaluated.

Int(1/((x+1)²(x-1)⁴)^1/3,x) doesn't get evaluated. Expected answer is -3/2*((x+1)/(x-1))^1/3.

Int(1/((x-1)³(x+2)⁵)^1/4,x) doesn't get evaluated. Expected answer is 4/3*((x-1)/(x+2))^1/4.

Int(1/((x-1)⁷(x+1)²)^1/3,x) doesn't get evaluated. Expected answer is 3/16*(3x-5)/(x-1)*((x+1)/(x-1))^1/3.

Int(1/((x-1)²(x+1))^1/3,x) doesn't get evaluated. Expected answer is related to ln and arctan, but a bit long so I'm not writing it here.

Int((x+1/x)/sqrt((x+1)³(x-2)),x) doesn't get evaluated. Expected answer is -4/3*sqrt((x-2)/(x+1))+sqrt(2)*arctan((2x+2)/(x-2))+2*arcsinh((x-2)/3)

Int(((x-1)²(x+1))^1/3/x²,x) doesn't get evaluated. Answer is bulky but exists.

Int(1/sqrt((x²-2x-3)⁵),x) doesn't get evaluated. Expected answer is (1-x)/(12sqrt((x²-2x-3)³))-(1-x)/(24sqrt(x²-2x-3))

Int(1/sqrt(x³-5x²+3x+9),x) doesn't get evaluated. Expected answer is arctanh(sqrt(x+1)/2)

Int(1/sqrt((x³-5x²+3x+9)³),x) doesn't get evaluated. Expected answer is (15x²-70x+43)/(256(x-3)²sqrt(x+1))+15/512*arctanh(sqrt(x+1)/2)

Int(1/(x³-5x²+3x+9)^1/3,x) doesn't get evaluated. Expected answer is -3/2*ln((x-3)^1/3-(x+1)^1/3)+sqrt(3)arctan((2*(x-3)^1/3+(x+1)^1/3)/(sqrt(3)*(x+1)^1/3))

Int(1/(x³-5x²+3x+9)^2/3,x) doesn't get evaluated. Expected answer is -3/4*((x+1)/(x-3))^1/3

Int(1/(x³-5x²+3x+9)^4/3,x) doesn't get evaluated. Expected answer is 3/320*(9x²-42x+29)/((x-3)*(x³-5x²+3x+9)^1/3)

Int(1/((x²+4)sqrt(1-x²)),x) doesn't get evaluated. Expected answer is 1/(2sqrt(5))*arctan(x*sqrt(5)/(2sqrt(1-x²)))

 

Well, this many so far. I will add any other ones that I happen to find.

Edited by quinyu, 10 April 2016 - 09:06 PM.

[mikbot]

When tring to define some functions, I kept getting odd results and I found out that mod(x,y) simplifies to just x?

Its very weird.

I managed to work around it by making my own mod function thats just:
y*(x/y - int(x/y))
and works for my function.

[pawel250]

Hi, 

I didnt find other bug report thread dedicated to my casio model so I try to report it here, probably you can have the same issue.

Bugs are linked to hexadecimal system.
 

First bug:

Addition 7FFFFFFF + 1 ends up as math error. 

Addition 80000000 + 1 ends up with success (it is ok)

Please see the movie in 41st second:

https://youtu.be/9goVj_DwhEw?t=41

 

Second bug:

Converting from hex system to binary system.

Cannot convert FFFF to binary. It ends up as math error.

Convertion from FFF to binary ends up successfully (it is ok).

 

This movie shows the problem in 22'nd  second :

https://youtu.be/9goVj_DwhEw?t=22

 

Mentioned problems I verified in fx-570es and fx-991 CE X models only, but is huge risk that all Cisco calculators have these problems.

 

Regards

Pawel