Turn on thread page Beta
    • Thread Starter
    Offline

    1
    ReputationRep:
    Prove that

    cosec2X+cot2X=cotX

    How to prove it?
    Offline

    12
    ReputationRep:
    (Original post by superkillball)
    Prove that

    cosec2X+cot2X=cotX

    How to prove it?
    Erm...this is P2 for me from last year....try using the double angle formulae for cosec2x (1/sin2x) and cot2x (1/tan2x)....then see if they cancel to give 1/tanx??

    G
    Offline

    10
    ReputationRep:
    LHS = cosec2x + cot2x = 1/sin2x + cos2x/sin2x = (1 + cos2x)/sin2x = 2(1 - sin^2x)/2sinxcosx = 2cos^2x/2sinxcosx = cosx/sinx = cotx = RHS.
    Offline

    12
    ReputationRep:
    (Original post by Ralfskini)
    LHS = cosec2x + cot2x = 1/sin2x + cos2x/sin2x = (1 + cos2x)/sin2x = 2(1 - sin^2x)/2sinxcosx = 2cos^2x/2sinxcosx = cosx/sinx = cotx = RHS.
    Yeh...that's what i was thinking....

    G
    • Thread Starter
    Offline

    1
    ReputationRep:
    thank you
 
 
 
Turn on thread page Beta
Updated: March 13, 2004
Poll
Could you cope without Wifi?
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

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

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