[3.3] Delete Matrix Rows And Columns; [3.4] Reverse List Elements; [3.5] Unexpected Newmat() Operation In Cylindrical And Spherical Vector Modes - Texas Instruments TI-89 Tip List

Once you have found the index, you can find the corresponding table x-value from
x = dx ( index − 1 ) + x1
If the target x is less than the first x-value in the table, the equation returns zero. If the target x is
greater than on equal to the last x-value in the table, the equation returns an index larger than the table
size. Your program should check for these conditions and handle them appropriately.

[3.3] Delete matrix rows and columns

There is no built-in function to delete a matrix row. This will do it:
mrowdel(m,r)
Func
Return when(r=1 or r=rowDim(m),subMat(m,mod(r,rowDim(m))+1,1,rowDim(m)-1+mod(r,
rowDim(m))),augment(subMat(m,1,1,r-1); subMat(m,r+1,1)))
EndFunc
m is the matrix, and r is the number of the row to delete. You will get a Domain error message if r is
less than or equal to zero, or greater than the number of rows of matrix m.
You can also use mrowdel() to delete a column, by finding the transpose, deleting the row, then finding
the transpose again, like this:
(mrowdel(m,c))→n
This deletes column c of matrix m.
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[3.4] Reverse list elements

Use this function
listrev(l)
Func
©(list) reverse list elements
seq(l[i],i,dim(l),1,⁻1)
EndFunc
to reverse the elements of list l. For example, listrev({1,2,3,4,5}) returns {5,4,3,2,1}
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[3.5] Unexpected NewMat() operation in Cylindrical and Spherical vector modes

If you use NewMat(1,2) to make a new matrix in the Rectangular vector format mode, you get [[0,0]] as
expected. But if the vector format mode is set to Cylindrical or Spherical, you'll get
[[0,∠R▶Pθ(0,0)]]
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