@vv thank you!

I see this link, but it is 3rd party package.

So, there is no way to expand into Fourier Series with built-in function?

@vv Could you please give me a link?

@nm what Maple ver are you using?

I use lastest ver 2020.1 and see this:

@Kitonum Thank you!

I can't belive it! No Fourier Series in Maple!!! What a shame!

@Thomas Richard  Thank you!

@tomleslie Thank you!

with(LinearAlgebra):

f := unapply(Determinant(M), w1, w2)

First fail:

with(LinearAlgebra):

But how to make a function f(w1,w2)?

f := (w1, w2) -> Determinant(M) doesn't work

@acer Thank you!

@dharr yes, thank you!

@dharr thank you for you reply!

Ok, we have a matrix as you present. I just want to manipulate with indexes i and j only and get the elements in zig-zag order.

In you example if we want to travers the matrix in zig-zag order we get

1 -> (4), 2 -> (4), 3 -> (16), 4 -> (49), ...

Elements of matrix maybe changed but not zig-zag order of elements.

A[2,1] always have a position 3 (please see above) when we travel in zig-zag order.

My question is - in there is any way to manipulate only with indexes i and j and get the order of element (it will be always constant).

@acer THANK YOU!!!

@acer thank you!

But why the graph is flat?

Usually it looks like this:

@acer Thank you for you reply!

Initialy I want to plot 3D plot were the modulus and argument are used to get the height and shading color respectively but now could help me please with both kinds of plot... Thank you!

@vv Thank you! It is very usefull!