My Math Forum  

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

Trigonometry Trigonometry Math Forum


Reply
 
LinkBack Thread Tools Display Modes
June 20th, 2017, 04:44 PM   #1
Newbie
 
Joined: Jun 2017
From: San Jose

Posts: 1
Thanks: 0

Trigonometry proof

Using Only the definition of the trigonometric functions in terms of

exp(x): cotx= -i(e^-ix+e^ix) /(e^-ix-e^ix)

Prove:

(cotx - 1)/(cotx + 1) = cos2x/(1 + sin2x)

Last edited by skipjack; June 20th, 2017 at 10:41 PM.
pranavoreos is offline  
 
June 20th, 2017, 10:47 PM   #2
Global Moderator
 
Joined: Dec 2006

Posts: 18,145
Thanks: 1418

This is straightforward. Can you post your attempt?
skipjack is offline  
June 21st, 2017, 05:51 AM   #3
Math Team
 
MATHEMATICIAN's Avatar
 
Joined: Jul 2013
From: काठमाडौं, नेपाल

Posts: 872
Thanks: 60

Math Focus: सामान्य गणित
Probably its:

(cotx - 1)/(cotx + 1) = cos2x/(1 +i sin2x)
MATHEMATICIAN is offline  
Reply

  My Math Forum > High School Math Forum > Trigonometry

Tags
proof, trigonometry



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
trigonometry proof Inflekx12 Trigonometry 2 July 6th, 2016 08:44 PM
Vector Trigonometry proof Daltohn Trigonometry 8 December 13th, 2013 06:08 PM
trigonometry rakmo Trigonometry 4 November 24th, 2013 05:34 AM
Trigonometry hoyy1kolko Algebra 2 February 10th, 2011 06:42 PM
trigonometry proof MarsTeam Algebra 1 May 3rd, 2010 10:44 AM





Copyright © 2017 My Math Forum. All rights reserved.