# Create 2D View of 3D Vector?

Dave Yrueta shared this question 2 months ago

Two questions:

1) Why is the 2D view in the attached file created from eq:1 blank? How can I make it visible?

2) Can you show side by side the 2D vector produced by multiplying a 3D vector by a 2x3 matrix?

Thanks

1

I've posted to this forum several times already; each time my questions are vetted for hours before allowing to appear. Why are my questions on moderation for so long?

1

Well, there's no guaranteed GG 24h surveillance. Moderation is done by some team members, developpers and volonteers as I am one. I happen to live in Belgium and have some night rest and GG-free time during the day according to my time zone. Probably it's the same for others who're in. That's all

chris

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Understood. I misunderstood the policy regarding account holders who have already asked approved question. Thank you for clarification.

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Hi Dave,

your 2d View from the plane eq 2 is empty, because there are no objects in it, except the plane itself. You can currently show grids and axes on that View, but nothing else. Try creating a point on that plane, e.g. Point(eq2): this point will be shown both in 3D and 2d Views.

I think that what I've written above answers also your other question :smile: if you create a 2d View from a plane containing your vector.

Please use CAS for products of non-square matrices * vectors.

https://wiki.geogebra.org/e... (using the input line you can multiply only 2x2 or 3x3 matrices by a vector)

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Please have a look at the sample file attached. Just a little rework of yours.

Open the CAS View to see the definition of the product.

I have created a vector u as product, then a plane through it, and a 2d view of the plane, where the vector, which lies on it, is visible. Is this what you want?

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Very kind of you to rework my example! Yes, (I believe) with a little reworking, this is exactly what I want.

I'm don't know how to "open the CAS View." I can see how to open the CAS calculator, but your file crashes when opened in that application. Is there a setting in 3D Calculator to open the CAS view?

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without CAS you can use vector(A v)

for A 2x3 matrix and vector v in R3 the result is in R2 in graphics window

Files: foro.ggb
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Thank you mathmagic! I've opened your form.ggb file in Calculator 3D, but don't know how to open a R2 graphics window. The only way I know how to do this is by right clicking an expression and then selecting the "Create 2D view from..." option. I've tried to doing that for each expression in your file, but that option doesn't appear. Am I missing something?

1

sorry, I use the clasic version 5 only

try typing setperspective("AGT")

the windows system in app works different for smatphones and tablet

you can see diferences here

https://www.geogebra.org/m/shfwqcpr

1

OK, that was amazing. Thank's so much!