PRECAL
posted by MELEK .
How can I solve this questions and get those answers????
answers
sec 13pi/4=? =>ã(2)
csc 13pi/4=? =>ã(2)
sec (pi/6)=? =>2ã(3)/3

13/4 = 3 1/4 = 2 + 1 1/4
so twice around + pi + pi/4
which is
45 degrees below x axis
cos 5 pi/4 = 1/sqrt 2 so sec 5 pi/4 = sqrt 2
the others are similar
Just remember once all the way around is 2 pi and halfway around is pi