# sec x

• Aug 18th 2009, 08:10 PM
netbook
sec x
sec x is undefined for

0 degrees
45 degrees
90 degrees
135 degrees
180 degrees

anyone know this rule want to help me out?
• Aug 18th 2009, 08:11 PM
Chris L T521
Quote:

Originally Posted by netbook
sec x is undefined for

0 degrees
45 degrees
90 degrees
135 degrees
180 degrees

anyone know this rule want to help me out?

$\sec x$ fails to exist when $\cos x=0$.

What do you think the values are now?
• Aug 18th 2009, 08:35 PM
netbook
could it be for 90 degrees i think the graph of the sec of x has a vertical asymptote at 90 right???
• Aug 18th 2009, 08:36 PM
Chris L T521
Quote:

Originally Posted by netbook
could it be for 90 degrees i think the graph of the sec of x has a vertical asymptote at 90 right???

Yup, its $90^{\circ}$.
• Aug 18th 2009, 09:29 PM
nikhil
Quote:

Originally Posted by netbook
could it be for 90 degrees i think the graph of the sec of x has a vertical asymptote at 90 right???

even without graph
sec(90)=1/cos(90)=1/0 (as cos(90)=0)
since 1/0 is undefined therefor secx is also undefined for x=90 degrees
• Aug 24th 2009, 06:44 AM
pacman
netbook, look at this. Just click the attachment to enlarge