# Trig/limits

• Sep 15th 2008, 06:09 PM
jarny
Trig/limits
Can someone help me prove that the limit of (1-secx)/x^2 = -1/2. as x approaches 0, i know (1-cosx)/x^2 is 1/2, and thats it. thanks a bunch.

I believe you can use identities or squeeze method, whatever you prefer
• Sep 15th 2008, 06:11 PM
Jhevon
Quote:

Originally Posted by jarny
Can someone help me prove that the limit of (1-secx)/x^2 = -1/2. as x approaches 0, i know (1-cosx)/x^2 is 1/2, and thats it. thanks a bunch.

I believe you can use identities or squeeze method, whatever you prefer

$\displaystyle \sec x = \frac 1{\cos x}$

plug that in and simplify. the result follows quickly (you will end up with something times the negative of the other limit you mentioned)

by the way, you need to say what limit you are taking. the limit as x goes to what?
• Sep 15th 2008, 06:12 PM
o_O
Quote:

Originally Posted by jarny
Can someone help me prove that the limit of (1-secx)/x^2 = -1/2. as x approaches 0, i know (1-cosx)/x^2 is 1/2, and thats it. thanks a bunch.

I believe you can use identities or squeeze method, whatever you prefer

(Talking)
• Sep 15th 2008, 06:14 PM
Jhevon
Quote:

Originally Posted by o_O
(Talking)

My apologies to Jarny (Bow) and my thanks to o_O (Handshake)

note to self, read the entire question! words can be boring yes, but if you don't, you'll end up looking like an idiot