My Math Forum  

Go Back   My Math Forum > High School Math Forum > Trigonometry

Trigonometry Trigonometry Math Forum


Thanks Tree1Thanks
Reply
 
LinkBack Thread Tools Display Modes
May 5th, 2018, 02:00 PM   #11
Senior Member
 
Joined: May 2016
From: USA

Posts: 1,126
Thanks: 468

Quote:
Originally Posted by Kavesat View Post
Thanks for reply, sir. Yes, I have learned some lim like this.


Sorry, I can't totally understand what you mean about Σ.
If the following Σ is right, why can't you directly replace the k with cos(k) and then calculate?


if you can replace, the value will go down - then go up + between -1 and 1...They will neutralize each other.
cos1=0.54030230586
cos2=-0.41614683654
cos3=-0.9899924966
cos4=-0.65364362086
cos5=0.28366218546
cos7=0.75390225434
You can of course compute the various cos(k) and add them up to get approximate numeric values. That does not necessarily mean that the sums can be condensed into a simple expression, a so-called closed form.

No, the sums do not neutralize each other, whatever that means. It is true that the various sums oscillate and are sometimes positive and sometimes non-positive, but the oscillation continues forever. It doesn't get to zero and then stay there.
.
JeffM1 is offline  
 
Reply

  My Math Forum > High School Math Forum > Trigonometry

Tags
cos, exist



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Does there exist a sequence? neelmodi Pre-Calculus 7 December 23rd, 2015 04:22 AM
Proving that nothing does not exist charlie_sheep Art 10 December 12th, 2015 01:46 AM
Does Empty Set Exist? intuit Real Analysis 4 July 9th, 2014 02:31 PM
0/0 does not exist? Dart Plegius Algebra 4 June 19th, 2012 12:37 PM
does there exist a function....? eric3353 Real Analysis 0 February 12th, 2012 06:04 AM





Copyright © 2018 My Math Forum. All rights reserved.