# How can I represent vector

x1=c(4,-1,3)
x2=c(1,3,5)
x=c(x1,x2)
data=matrix(x,ncol=2,byrow=FALSE)
transport_data=t(data)
How can I do to represent vectors of variable x1,x2?

The `data` object that you made with matrix() gives you `x1` and `x2` vectors arranged in a columnar fashion
similarly
The `transport_data` object that you made by transposing `data` is a rowwise matrix that represents `x1` and `x2`

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I have to create variable's span

I commit an error I need observations span

Its very unclear what you mean.
what are the 'observations' in this context ?

and aren't "spans" in linear algebra all the possible linear combinations of the vectors ? Mustn't the answer therefore be somewhat algebraic, because if you tried to enumate them, it would be infinite... ?

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Hi, and welcome!

Here's a bit more compact way to do this, and if you want to unpack one of the four vectors, you would call them with

``````x1 <- c(4,-1,3)
x2 <- c(1,3,5)
m <- t(cbind(x1,x2))
m
#>    [,1] [,2] [,3]
#> x1    4   -1    3
#> x2    1    3    5
m[1,]
#>   4 -1  3
m[2,]
#>  1 3 5
m[,1]
#> x1 x2
#>  4  1
m[,2]
#> x1 x2
#> -1  3
``````

Created on 2020-02-22 by the reprex package (v0.3.0)

I would obtain a triplot whit 2 points that represent my variables x1 and x2 and arrows that link point (0,0,0) with x1 and (0,0,0) with x2

Are you trying to create a `graph` object? (Sometimes referred to as a network representation.)

I think @Daniel96 means he's trying to create a 3D plot with two (geometric) vectors, one from the origin to the point x1, and one from the origin to the point x2. I can help with a 2D version, but I have no idea how to help with a 3D version, however.

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I tried with scatterplot3d()
But I don't have any idea how can I represent vectors in R3

``````
x1 <- c(4,-1,3)
x2 <- c(1,3,5)
origin <- c( 0, 0, 0)
m <- t(cbind(x1,x2,origin))

scatterplot3d(m,
type="p",
color = c("red","blue","black"),
pch = 1,
xlim = c(-6,6),
ylim = c(-6,6),
zlim = c(-6,6))
`````` I'm afraid I don't know what a triplot is but this is a scatterplot3d

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Here's a post on Stack Overflow about drawing 3D vectors with a package called `rgl` -- maybe try that?

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