TI-36X Pro Calculator Problem

Thread Starter

SamR

Joined Mar 19, 2019
4,484
It's what I use mostly for solving problems along with Microsoft Mathematics on my computer and also have the TI-nspire CXII CAS calculator. Here is the problem...
1662145086820.png
Yes I know how to solve it manually a=1662146324320.png

But how can I get the TI-36 calculator to do it? I've tried using its Numeric equation solver but got an Invalid Domain Error so I'm not doing it correctly?

Edited to remove ambiguity
 
Last edited:

WBahn

Joined Mar 31, 2012
27,862
I'm not familiar with the notation you are using.

When you say

solve( a = f(x,y), a)

What, exactly does that mean? What is it that you are solving for?
 

Thread Starter

SamR

Joined Mar 19, 2019
4,484
Here is the initial expression in MS Mathematics
1662189392705.png
Which it then translates to
1662189640322.png
Which it then solves as
1662189694721.png
Right back where we started! What I am trying to get it to resolve to is
1662189918373.png
Which MS Mathematics then solves as
1662190098654.png
I guess what I am looking for is the complex form of the simplified equation? Instead, it wants to simplify the simplified equation which it cannot do since it is already in the simplified form. The TI-36 has some solving abilities but it gives me an Invalid Domain Error. So, I was hoping someone had an answer as to how to get the complex form on the TI-36. Sometimes learning how to use the machine to save time takes longer than just doing it by hand!
 

WBahn

Joined Mar 31, 2012
27,862
I'm still unclear as to what it is that you are looking for.

How does a = (y+2x)/(xy) constitute any more of a solution to anything than a = 1/x + 2/y does?

Given the variables and the general form of the equation, this looks like the equations for a curve in the xy-plane given some parameter 'a'.

For instance, if we had a = x^2 + y^2, this would describe a circle having a radius of sqrt(a).

Looking at what you are given:

a = 1/x + 2/y

We see that neither x nor y can be zero.

We also see that if x = 1/a that y must be infinite and, similarly, if y = 2/a that x must be infinite.

So we have two asymptotes, a vertical one at x = 1/a and a horizontal one at y = 2/a.

We can then solve for y(x) and get

y = 2x/(ax-1)

If we plot this, we get the following for a = 5.

The vertical line at x = 1/a = 0.2 is an artifact of how the plot was generated. That should be a dashed line indicating the vertical asymptote. Furthermore, there should be a circle at the origin since the original function is not defined there.

1662196753955.png

Does any of that help you at all?
 

Thread Starter

SamR

Joined Mar 19, 2019
4,484
Not really. I'm not interested in plotting it and yes, MS Mathematics can do that. What I was looking for is, using the TI-36, MS Mathematics, or TI-nspire, how do I (if possible) use them to translate
1662212875570.png
into a single expression of
1662212927724.png
I'm sorta going backwards from simplified expression to complex expression which is the antithesis of what the calculators normally do and not covered in their documentation that I can find.
 

crutschow

Joined Mar 14, 2008
31,111
I'm sorta going backwards from simplified expression to complex expression
I doubt you will find any program to do that since, as you say, it's going backwards.

So why do you want to go backwards?
It's sort of like uncooking an egg.
 

Thread Starter

SamR

Joined Mar 19, 2019
4,484
Yup, it is. It was a problem that I was given to solve with the calculator in a John Bird book "Electrical Circuit Theory and Technology". Unless someone knows a trick, I agree, I don't think it can be. I've spent far too much time trying to do that with the calculator, reading manuals, and researching to find a method when it is a very simple expression to resolve manually on a scratch pad and in my head.
 
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