17 replies to this topic

[Horny_Master]

i have an 9970-g and i need to find the third square root of i (imaginary number)
by typing

(3) -> (SHIFT) -> (^) -> (OPTN) -> (CPLX) -> (i)

i only get a MATH ERROR. what shall i do?



please help, greg from lake constance.

[Andy.Davies]

i have just preformed the calculation on my AFX, here is the result:

0.8660254038+0.5i

[Overlord]

it's because the CFX is not adapted for complex calculations.

third roots of i :

-i
-sqrt(3)/2 + i/2
sqrt(3)/2 + i/2

[CrimsonCasio]

I wasnt aware that any CFX model could do complex numbers...


----------EDIT-----------
overlord beat me to it...

[Horny_Master]

tx - seems i need an afx.

is afx = algebra fx 2.0 ????

[Overlord]

afx = algebra fx

so algebra fx 2.0 is one of the AFX model calcs

[Andy.Davies]

i just tryed the cubed root of i on my FX9750G and i just got a maths error. so it looks like you will need an AFX

[casiokingdom]

it's because the CFX is not adapted for complex calculations.

well, i am just learning complex numbers at school now with my CFX, and we can do simple complex number calculations with the CFX.

eg. (4+5i)(5+3i) or division or just plain + and -.

We will use progs for the other more complicated stuff like roots, powers.

i'll may be able to answer you question soon, if i learn about third root of i

[Horny_Master]

Yes the (second) square root of i ist possible, too. But the thirt etc. not.... Thats a little bit disappointing =(

[coco]

Hi, I have a CFX-9970G also and did the following:

Went into CAS mode
Set answers to complex mode
typed solve(x^3=i,x)

Well, the calc did not bring the correct answer but the output was very interesting (too long to type) so I suggest Horny to try what I did.

Greets

Coco

[Overlord]

you can find xth (not xthunder28) roots of complex numbers with the calc :

z=a+bi, you want the xth roots of z.

you convert z=a+bi in z = r*e^(i@) = r*cis(@)=r*(cos(@)+isin(@) (it's the same)

- Pol(a,b) will give as result List Ans={r,@} **** (menu angle)
- Abs(a+bi) will give as result Ans=r **** (menu cplx)
- Arg(a+bi) will give as result Ans=@ **** (menu cplx)
- AFX : you have a command to convert automatically z=a+bi in z=r*e^(i@)=r*cis(@)

(check rad/deg mode, i work in rad)

z = r*cis(@) = r*cis(@+2kpi) **** k integer

the x xth roots of z are :
x1 = x-root( r )*cis( (@+2kpi)/x ) [for k=0] = x-root( r )*cis( @/x )
x2 = x-root( r )*cis( (@+2kpi)/x ) [for k=1] = x-root( r )*cis( @/x + 2pi/x)
x3 = ...
x4 = ...

then you can convert it x=c+di
- Rect(r,@) will give as result List Ans={c,d}
- ReP(r*cis(@)) will give as result Ans=c
- ImP(r*cis(@)) will give as result Ans=d
- AFX : you have a command to convert automatically x=r'*e^(i@')=r'*cis(@') in z=c+di


nota : i had a problem while typing this post, when i type ( r ) without the spaces, it automatically convert it in ®

[Horny_Master]

many thanks, lets try it...




p.s. to coco: where can I set answer to complex mode?

[coco]

From the main menu:

1. Choose option D (ALGBR) -- enters in ALGEBRA mode
2. Press Shift' /> MENU' /> -- enters the SETUP menu (press shift key first then menu key)
There are three options there: Angle (default is Rad), Answer type (default is Real) and Display (default is Norm1)
3. Highlight 'Answer type' then press F2 (this will change answer type to Complex)
4. Press EXIT

That's it.

Good luck

[Horny_Master]

many thanks for your help - learning complex numbers by trying to calculate them with the cfx is a pretty pedagocila thing =)

[coco]

You can also make a program with the info that Overlord posted (Thanks Overlord!!). I made one and it works quite well

Coco

[Horny_Master]

@overloard
thanks very much


@coco

i'm not very good in programming with the calc yet. could you send me the program? admin AT greg-bala.de thanks.

[casiokingdom]

visit http://www.charliewa...io/casprog.html and download his calc.cat package. in there you will find a prog named complxnum. that will solve your equation for you. i just learnt today in school how to do it with the prog. very useful.

[coco]

@ Horny_Master: I've sent you the program but I think that the one CasioKingdom suggests is a lot easier to use. Anyway let me know if you find bugs.

Coco.