# Julia-Doku: determinates of a matrix

**URL:** <https://discourse.julialang.org/t/julia-doku-determinates-of-a-matrix/15384>\
**Category:** New to Julia\
**Tags:** linearalgebra\
**Created:** [September 23, 2018, 3:04pm UTC](https://discourse.julialang.org/t/julia-doku-determinates-of-a-matrix/15384 "2018-09-23T15:04:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Gunter\_Faes](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunter_faes/32/12580_2.png) [@Gunter\_Faes](https://discourse.julialang.org/u/Gunter_Faes)\
**Post date:** [September 23, 2018, 3:04pm UTC](https://discourse.julialang.org/t/julia-doku-determinates-of-a-matrix/15384/1 "2018-09-23T15:04:33Z")

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Hello, I am (still) a bloody Julia beginner (V 1.0.0 2018-08-08) and would like to cook the example from the linear algebra of the [Julia documentary](https://docs.julialang.org/en/stable/stdlib/LinearAlgebra/#Linear-Algebra-1). It is about the determination of the determinants of the example:

```julia
julia> A = [1 2 3; 4 1 6; 7 8 1]
3×3 Array{Int64,2}:
 1 2 3
 4 1 6
 7 8 1

julia> det(A)
104.0

```

I get the following error message:

```julia
julia> det(A)
ERROR: UndefVarError: det not defined

```

I’ve noticed that the syntax for some features has been changed to Julia 1.0.0. Is that also the case here?  
Sorry for this - hopefully - simple question!

Best Rgeads,  
Guenter

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**Author:** ![nalimilan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nalimilan/32/147_2.png) [@nalimilan](https://discourse.julialang.org/u/nalimilan)\
**Post date:** [September 23, 2018, 3:05pm UTC](https://discourse.julialang.org/t/julia-doku-determinates-of-a-matrix/15384/2 "2018-09-23T15:05:23Z")

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You need to call `using LinearAlgebra`. The docs should be improved to explain this for each stdlib module.

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<div class="post-metadata">

**Author:** ![Gunter\_Faes](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunter_faes/32/12580_2.png) [@Gunter\_Faes](https://discourse.julialang.org/u/Gunter_Faes)\
**Post date:** [September 23, 2018, 7:21pm UTC](https://discourse.julialang.org/t/julia-doku-determinates-of-a-matrix/15384/3 "2018-09-23T19:21:45Z")

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Thanks for your support! Worked!