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#1 2007-01-24 11:24:27

Toast
Real Member
Registered: 2006-10-08
Posts: 1,321

Graphing Sum 'n Product

Does anyone know how I might be able to graph a sum or product on a graphics calculator?

For instance, I type in

on my TI-89 but it won't appear at all.

(Btw was there a calculator forum in the past? I can faintly remember there being one)

Last edited by Toast (2007-01-24 11:26:06)

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#2 2007-01-24 11:47:05

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: Graphing Sum 'n Product

I don't have a TI-89, so I wouldn't know the intricacies of that particular calculator, but I would think that the problem might be because the use of the summation sign means that the function is discontinuous.

So if you tried to graph it then you'd get a bunch of points rather than a curve, and your calculator might not like that.

I don't remember there ever being a calculator forum. If there was, I don't see why it would have been closed. Maybe there was a calculator topic in one of the boards at some point.


Why did the vector cross the road?
It wanted to be normal.

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#3 2007-01-25 04:51:09

Ricky
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Registered: 2005-12-04
Posts: 3,791

Re: Graphing Sum 'n Product

On a Ti-89, what you can do is create an array of points:

[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

And a second array:

[1, 5, 14......]

And then plot them (go to Y=, and then up above the equations) with the first on the x-axis and the second on the y-axis.


"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

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#4 2007-01-25 13:22:56

Toast
Real Member
Registered: 2006-10-08
Posts: 1,321

Re: Graphing Sum 'n Product

How do you set up an array of points?

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#5 2007-01-25 14:54:45

Ricky
Moderator
Registered: 2005-12-04
Posts: 3,791

Re: Graphing Sum 'n Product

Ah, sorry.  It's:

{1, 2, 3}->x

Where "->" is the STO> button.


"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

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