Trigonometric identities

Announcements
    • Thread Starter
    Offline

    1
    ReputationRep:
    Prove the following identity:
    (1-cosx) / (1+cosx)= tan^2(x/2)

    Thanks in advance
    Offline

    3
    ReputationRep:
    Know any double angle formulae for cosine to get rid of the +1 and -1 in the numerator and denominator?
    • Thread Starter
    Offline

    1
    ReputationRep:
    yes, but i don't understand how they fit in this identity
    Offline

    3
    ReputationRep:
    (Original post by Stanspam)
    yes, but i don't understand how they fit in this identity
     \cos x \equiv 2\cos^2 (x/2)-1\equiv 1-2\sin^2 (x/2) .
    Use each one of these identities on numerator or denominator to get rid of the constants.
    • Thread Starter
    Offline

    1
    ReputationRep:
    Got it! Thank you so much
 
 
 
Write a reply… Reply
Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: September 24, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Today on TSR
Poll
Does your body insecurities make you avoid PE or exercise?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.