Hello,

I can not see why roots() is working wrong with the second guess value.
Could someone reproduce this please, or tell me if I am doing anything wrong.
If you can reproduce - this might be a bug, or something wrong with my computer (WinXp, SMath v0.89.8 Portable).

Regards,
Radovan

Hi Radovan

I've just done a very quick check and I get exactly the same results you show using
Smath 0.89 build 8
Windows 7

I don't know why this should happen, sorry.

Brian

Thank you Brian,

This is a Live version:
[LIVE width=347 height=197]http://smath.info/live/?file=2865[/LIVE]
Hmm...it seems that is definitely a bug.
With another function - it is Ok
[LIVE width=302 height=285]http://smath.info/live/?file=2870[/LIVE]
Regards,
Radovan

Strange? If the 2 in denominator is changed a bit - it is OK???
[LIVE width=407 height=275]http://smath.info/live/?file=2872[/LIVE]
Regards,
Radovan

I am using the beta version and do not get this error. In both cases root = +- 2.83 (with b=1, c=1)

Hello,

Wrote

I am using the beta version and do not get this error. In both cases root = +- 2.83 (with b=1, c=1)

Take a look at the previous example, please. If you use b=1, c=1 the result is correct, but if you use b=1, c=2 then it is not correct.

[MATH=eng]f(a,b,c):{a^2-2*b}/{2+c}-2[/MATH]
[MATH=eng]b:1[/MATH] [MATH=eng]c:1[/MATH]
[MATH=eng]roots(f(x,b,c),x,-10)=-2.8284[/MATH]
[MATH=eng]roots(f(x,b,c),x,10)=2.8284[/MATH]
[MATH=eng]b:1[/MATH] [MATH=eng]c:2[/MATH]
[MATH=eng]roots(f(x,b,c),x,-10)=-3.1623[/MATH]
[MATH=eng]roots(f(x,b,c),x,10)=10@#[/MATH] - WRONG

or

[MATH=eng]roots(f(x,b,c),x,10000)=10000@#[/MATH]

but if you put something like

[MATH=eng]f(a,b,c):{a^2-2*b}/{2.0000000000001+c}-2[/MATH]

the result is RIGHT! Moreover, Instead of 2+c in the denominator you can put 4+c, 6+c -4+c or any other even number instead of 2 and there will be wrong again. If you put any odd integer (positive , negative) or a real number, the result will be right.There must be some bug here.

[MATH=eng]roots(f(x,b,c),x,10000)=3.1623@#[/MATH]

On the other hand

[MATH=eng]solve(f(x,b,c),x,-100,100)=mat(-3.1623,3.1623,2,1)[/MATH]



Regards,
Radovan

Hello,

Unfortunately, It seems that the same bug is still present in the recent v0.90

Regards,
Radovan

Fixed.



Best regards, Andrey Ivashov.