Question 965606
Evaluate: sec^2 (-13(pi/6)) - csc^2 5pi/4
{{{csc^2 (5pi/4)=1/sin^2(5pi/4)=1/sin^2(pi/4)=1/(sqrt(2)/2)^2=1/(1/2)=2}}}
{{{sec^2 (-(13pi/6))=1/cos^2 (-(13pi/6))=1/cos^2(-pi/6)=1/(sqrt(3)/2)^2=1/(3/4)=4/3}}}
{{{sec^2 (-13pi/6) - csc^2 (5pi/4)=(4/3)-2=8/6-12/6=-4/6=-2/3}}}