#sec(x)=1/cos(x)#
#sec^2(x)=(1/cos(x))^2 = 1/cos^2(x) = 1/(cos(x))^2#
#sec(pi/4)=1/(cos(pi/4))^2# #=># #{cos(pi/4)=sqrt2/2}#
#sec(pi/4)=1/(sqrt2/2)^2#
#sec(pi/4)=1/(2^(2*1/2)/2^(1*2)#
#sec(pi/4)==1/(2^1/2^2)#
#sec(pi/4)=1/(2/4)#
#sec(pi/4)=1/(1/2)#
#sec(pi/4)=1/1 -: 1/2#
#sec(pi/4)=1/1 * 2/1#
#sec(pi/4)=2/1#
#sec(pi/4)=2#
Thus, we have our answer.