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HP 40gs how to get a submartix from a matrix
08-31-2023, 11:56 PM
Post: #4
RE: HP 40gs how to get a submartix from a matrix
Dear Thomas and Gilles,
Thank you both for your replies.
I learnt two new things:

In python, I learned a way of multiplying matrices:
To illustrate:
result = U @ M @ V
Is not the same as
result = U * M * V

In the first statement, the "@" does matrix multiplication.
But in the second statement, the "*" does element-by-element multiplication.

Also learnt that
result = V @ M @ U
produces
[[0 0 0] [0 0 0] [0 0 0]]

For the HP 40GS, one can do subsets of matrices:
[[1,2,3],[4,5,6],[7,8,9]] STO M1

MAKEMAT(M1,(I+1,J+1),2,2) STO M2. will produce a submatrix
[[5,6],[8,9]]

Question please
Is there a general method to get any 2x2 submatrix from a 3x3 submatrix using MAKEMAT?
Eg
[[1,3],[7,9]]

Thank you
Anthony ofvSydney
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RE: HP 40gs how to get a submartix from a matrix - Anthony The Koala - 08-31-2023 11:56 PM



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