Question

sec(pi/2-0) =

Answer 1

http://www.mathwords.com/c/cofunction_identities.htm

Answer 2

sec(pi/2-0)
sec(pi/2)
1/cos(90 degrees)
well cos of 90 degrees is 1 because cos=y and the y coord of 90 degrees on a unit circle is 1. so
cos(90')=1
1/cos(90')=1/1
=1