Question 641826
Find the exact value of the expression. 
sec^2 pi/4 - 6=
1/cos^2(&#960;/4)-6=
cos (&#960;/4)=&#8730;2/2
cos^2(&#960;/4)=2/4=1/2
1/(1/2)-6=2-6=-4
sec^2 pi/4-6=-4