Hey there! Sign in to join this conversationNew here? Join for free

Trigonometric proof Watch

Announcements
    • Thread Starter
    Offline

    2
    ReputationRep:
    Please help with this trigonometric proof!
    Prove that 2sinxcosx/tanx = 2-2sin^2(x)
    • Community Assistant
    Offline

    19
    ReputationRep:
    (Original post by gcsemusicsucks)
    Hope it helps!
    Please don't post full solutions.
    Offline

    14
    ReputationRep:
    (Original post by Mr M)
    Please don't post full solutions.

    It's considered poor form to work on both sides of an identity at the same time. Start on one side and work towards the other.
    Sorry! And I don't think I worked on both sides at the same time? I worked from the LHS
    • Community Assistant
    Offline

    19
    ReputationRep:
    (Original post by gcsemusicsucks)
    Sorry! And I don't think I worked on both sides at the same time? I worked from the LHS
    You didn't - it was my mistake, my head doesn't rotate 90 degrees very easily.
    Offline

    17
    ReputationRep:
    (Original post by gcsemusicsucks)
    Sorry! And I don't think I worked on both sides at the same time? I worked from the LHS
    Could you edit and remove your solution and just give a hint
    Offline

    18
    ReputationRep:
    (Original post by olympiad1357)
    Please help with this trigonometric proof!
    Prove that 2sinxcosx/tanx = 2-2sin^2(x)
    Division by tan is the same as multiplication by cot. Also consider using Pythagoras' identity.
    Offline

    14
    ReputationRep:
    (Original post by olympiad1357)
    Please help with this trigonometric proof!
    Prove that 2sinxcosx/tanx = 2-2sin^2(x)
    Could you perhaps use any trigonometric identities to help you move in the right direction?
    Offline

    14
    ReputationRep:
    (Original post by Desmos)
    Division by tan is the same as multiplication by cot. Also consider using Pythagoras' identity.
    I think talking about cot would be overcomplicating things. But yes Pythagoras' identity would be useful.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Should Spain allow Catalonia to declare independence?
    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
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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.