secd — Compute the element-wise secant of the argument given in degree.
y = secd(x)
The entries of y are thesecant
1/cos of the entries of x given in
degree. The results are real and in ]-%inf -1] U [1
%inf[. For entries equal to n*180 with
n integer, the result is exactly -1
or +1. For entries equal to n*90with
n integer and odd the result is infinite(or an error
depending on ieee mode).