Need help with TI-86

[somebody]

guys, i need your help to figure out if i can find an answer to question like...

 

[(S-3)(S-2)(S-3)]/[(S-3)(S+4)(S+5)(S+1-2J)(S+1+2J)]

 

 

!. How should i set this eqation, where i would put different values for S and J is a complex number so when i press enter i would get whatever this equals to?

 

thanks

[Pyrotex]

guys, i need your help to figure out ...put different values for S and J is a complex number ...

Well, for starters, let's clear up an uncertainty here.

You appear to be saying that S and J are complex numbers. Are they? Both of them or just one of them?

Assuming for the moment that S and J are both complex, then you would have two numeric values to enter for each: S = a + bi and J = m + ni

The most obvious way of entering these values is by designating four "registers" of your calculator like this for example:

Reg.3 -- a

Reg.4 -- b

Reg.5 -- m

Reg.6 -- n

You insert the complex number S into registers 3 and 4 -- and the complex number J into registers 5 and 6.

Your equation would calculate the final value from those four registers.

 

Does this help??

[somebody]

J is the imaginary and S is the value which i want to insert because the question asks that find the value between -2 to 2 so i have to insert -2,-1.5 and so on.

 

So first of all how would i set up [(S-3)(S-2)(S-3)]/[(S-3)(S+4)(S+5)(S+1-2J)(S+1+2J)]

in TI 86

 

Then how would i enter different S value to get final answer?

 

thanks

[Pyrotex]

J is the imaginary and S is the value which i want to insert...So first of all how would i set up [(S-3)(S-2)(S-3)]/[(S-3)(S+4)(S+5)(S+1-2J)(S+1+2J)]

...Then how would i enter different S value to get final answer?

Insufficient information.

Is the "final answer" to be a function of J, or a numeric answer?

 

If you expect to get a numeric answer, then you must also input a value for J.

 

Notice that J occurs only in the denominator and only in two terms:

(S+1-2J)(S+1+2J)

 

This is the same as {(S+1) - 2J} {(S+1) + 2J}

This equals {(S+1)^2 - (2J)^2 }

 

Now, as you said, J is "imaginary". Not complex (a + bi), but imaginary (bi).

Let's say therefore that J is actuall Ki, where i is the square root of minus one and K is now just a number.

 

Therefore J^2 = (Ki)^2 = -(K^2)

 

Therefore, our equation above becomes: {(S+1)^2+4K^2}

 

Your original equation, [(S-3)(S-2)(S-3)]/[(S-3)(S+4)(S+5)(S+1-2J)(S+1+2J)]

now becomes

 

[(S-3)^2 *(S-2)]/[(S-3)(S+4)(S+5)((S+1)^2+4K^2)]

 

Notice there are no more imaginary terms.

 

Assume you will put S in register 2,

Assume you will put K in register 3,

Now put your equation in in the following manner (I am assuming your TI calculator uses the same keys as the older TI-59

"REC" is the Recall key and is always followed by a register number

"STO" is the Store key and is always followed by a register number

"SQ" is the Square key

 

( ( REC 2 - 3 ) SQ * ( REC 2 - 2 ) ) = STO 1

( ( REC 2 - 3 ) * ( REC 2 + 4 ) * ( REC 2 + 5 ) *

( ( REC 2 + 1 ) SQ + 4 * REC 3 * REC 3 ) ) = STO 4

REC 1 / REC 4 =

 

The above should be keyed in in "equation program" mode.

 

Now, say that J is 7i, or that K is 7.

Enter:

7 STO 3

that puts K in register 3

 

Enter your first S value:

1.5 STO 2

 

Now press the calculate key, and the calculated value should appear.

 

This is not the only way to do your equation. I did the numerator and denominator separately, with numerator in register 1 and denominator in register 4. There are many, many other ways you can key it in.

[somebody]

Assume you will put S in register 2,

Assume you will put K in register 3,

 

 

umm.. when you say register you mean to store? if not, then how to make register key? also, what value should i store for S and K when i put them in register?

 

thanks for explanation, it is very clear.

[Pyrotex]

umm.. when you say register you mean to store? if not, then how to make register key? also, what value should i store for S and K when i put them in register?...

If your calculator doesn't have a Store X key and a Recall X key, then maybe you don't have registers.

 

In that case, every time I specify "REC 2", just plug in the value of S instead.

Every time I specify "REC 3" plug in K.

 

What values of S and K? Well, that should be part of the the problem itself! I can't help you there. In your first post you said something about plugging in values of S between 1 and 2 or something like that. Go back and read the original problem to find the PURPOSE of the problem. Just what is it the problem wants you to accomplish.

[somebody]

thanks

[pgrmdave]

I am assuming your TI calculator uses the same keys as the older TI-59

 

Pyro - the TI-86 is a graphing calculator, much more like the TI-83 and TI-82. It is fully programmable in a BASIC type language, it can store variables in letters, has graphing functions and mathematical functions. It also has a mode in which you can work directly with imaginary numbers (it's under the menu, there are a few different modes, one is "a+bi" mode).

[pgrmdave]

Now, I have quite a bit of experiance with the TI-83+, so I'm going to say what I would do on that - it will be a bit different on the 86, but not too much so.

 

I would put the calculator into a+bi mode, and enter the equation into Y1, using 'X' in place of S (assuming that you have a definite number for J, that is). From here you have two options: You can go to the graph, or you can exit to the main screen.

 

From the main screen you can go to varibles, find Y1 (it's probably under 'Y-variables', or 'Func', or some combination thereof). Hit enter and "Y1" will be on the screen. In front of it, put the number for S that you want to test in parenthesis ( Example: "Y1(3)" will return the Y value at X = 3 This will tell you what the entire function would equal if S was 3).

 

On the graph screen, you can either trace (which is difficult unless you adjust your X-Axis on the window screen so that 1 pixel = 1 X-Unit) or you can find the value at a point using the 'Calc' menu (I don't do this as much, so I can't necessarily guarentee this from memory).

 

 

If neither of these solutions are what you are looking for, it is always possible to write a program to do what you want - I'm not quite sure what you're looking for, so I didn't try to do that.