
Clojure Linear Algebra Refresher – Matrix Transformations - emidln
http://dragan.rocks/articles/17/Clojure-Linear-Algebra-Refresher-Matrix-Transformations
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dragandj
1 point by dragandj 7 hours ago | parent [-] | on: Clojure Linear Algebra
Refresher (3) – Matrix Tran...

This is part 3 of a series.

The first part can be found here: Clojure Linear Algebra Refresher (1) -
Vector Spaces

[http://dragan.rocks/articles/17/Clojure-Linear-Algebra-
Refre...](http://dragan.rocks/articles/17/Clojure-Linear-Algebra-Refresher-
Vector-Spaces)

The second part is here:

[http://dragan.rocks/articles/17/Clojure-Linear-Algebra-
Refre...](http://dragan.rocks/articles/17/Clojure-Linear-Algebra-Refresher-
Eigenvalues-and-Eigenvectors)

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Yetanfou
Am I missing something here or does the article open with a false statement:

    
    
       Consider a Clojure function (fn [x] (+ (* x x) 4)).
       The set of allowed values for x is called the domain
       of the function. For value 2, for example, the result
       is 16. We say that the image of 2 is 16.
    

As far as I can see the image of 2 is 8 for that function - and I don't even
program in Clojure. A Clojure repl [1] agrees:

    
    
       >  (defn squaredplusfour[x] (+ (* x x) 4))
       #'sandbox11276/squaredplusfour
       > (squaredplusfour 2)
       8
    
     [1] http://www.tryclj.com/

~~~
sooheon
Yep looks like a simple mistake.

> and I don't even program in Clojure

Congrats, you just did! :)

