My Math Forum limit (cos(1\x))|tan x| x--> .5pi

 Calculus Calculus Math Forum

 December 5th, 2010, 09:44 AM #1 Newbie   Joined: Dec 2010 Posts: 5 Thanks: 0 limit (cos(1\x))|tan x| x--> .5pi 1. having a hard time figuring out. I know the answer if infinite but having a hard time proving it 2. tan x = cot (.5pi - x) did not help 3. tried substituting t = 1\x got stuck thanks
 December 5th, 2010, 10:02 AM #2 Senior Member   Joined: Nov 2010 From: Staten Island, NY Posts: 152 Thanks: 0 Re: limit (cos(1\x))|tan x| x--> .5pi $\cos (1/x)$ approaches a positive finite number as $x\rightarrow \pi /2$. $|\tan x|$ approaches $+\infty$ as$x\rightarrow \pi /2$ So you can simply multiply the two limits. A positive finite number times $+\infty$ is $+\infty$.
 December 5th, 2010, 10:07 AM #3 Newbie   Joined: Dec 2010 Posts: 5 Thanks: 0 Re: limit (cos(1\x))|tan x| x--> .5pi thanks but i do not quiet understand what you mean i know the squeeze the theorem but i do not understand how to use it thanks
 December 5th, 2010, 10:14 AM #4 Senior Member   Joined: Nov 2010 From: Staten Island, NY Posts: 152 Thanks: 0 Re: limit (cos(1\x))|tan x| x--> .5pi Never mind - you don't need the squeeze theorem for this. I'm going to edit the above post with the solution which is much simpler.
 December 5th, 2010, 10:18 AM #5 Newbie   Joined: Dec 2010 Posts: 5 Thanks: 0 Re: limit (cos(1\x))|tan x| x--> .5pi Thats it? pretty simple! thanks
 December 5th, 2010, 10:26 AM #6 Senior Member   Joined: Nov 2010 Posts: 288 Thanks: 1 Re: limit (cos(1\x))|tan x| x--> .5pi hello there the limit is plus infinity

 Tags 5pi, cos1x|tan, limit, x>

### .5pi

Click on a term to search for related topics.
 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post panky Calculus 6 January 5th, 2012 04:35 PM superconduct Calculus 3 December 31st, 2011 10:11 AM veronicak5678 Real Analysis 4 August 22nd, 2011 10:07 AM Aurica Calculus 1 June 11th, 2009 12:17 PM conjecture Calculus 1 July 24th, 2008 01:14 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top