# [LON-CAPA-users] multiple response boxes

**Lon Mitchell
**
lon-capa-users@mail.lon-capa.org

*Fri, 03 Oct 2008 11:43:30 -0400*

What are the possible interactions among multiple response boxes in a
question? I have found examples of questions where a custom response
boxes are used, and a perl routine compares the separate inputs, for
example, to check the off-diagonal elements of a matrix to see if it is
symmetric, but this seems to limit the computer algebra system role in
evaluating the result. In particular, is it possible to have non-custom
response boxes interact?
For an example that might justify the above, what about asking "Give a
2x2 symmetric matrix with no zero entries and calculate its
characteristic polynomial" (perhaps this could be a leading question to
a discussion about symmetric matrix eigenvalues). We could use custom
response boxes to check that the matrix is symmetric and has no zero
entries using perl, but it would then be nice to invoke maxima to find
the characteristic polynomial and provide it to a standard formula
response box to check the other student entry.
Finally, are multiple response boxes the best way to ask for a matrix
answer?
Thanks,
Lon Mitchell