Turn on thread page Beta
    Offline

    18
    ReputationRep:
    (Original post by Barny)
    So it's x^2/2 for x > 0 but -x^2/2 for x< 0?

    Although, I'm still struggling to understand why exactly tan is a modulus here.

    Is it also true that sqrt(sec^2(x)) = |secx| for example?
    Yes, and \sqrt{x^2} = |x|

    And Matt, very funny, but my point was that limits are needed for it to make sense
    • Thread Starter
    Offline

    15
    ReputationRep:
    I always thought root(x^2) = +/- x which is slightly different to |x|, isn't it?
    Offline

    18
    ReputationRep:
    No, the square root symbol means the positive root, this is why there is a \pm symbol in the quadratic formula
    • Thread Starter
    Offline

    15
    ReputationRep:
    Well bugger me, fancy getting through 4 years of Maths without knowing that :p:

    So just to confirm, sqrt(x^2) = |x| is true for all x?
    Offline

    18
    ReputationRep:
    Yes. (All real x anyway) (Once we start dealing with complex numbers we sometimes give the \sqrt{} symbol completely different meanings)
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: August 31, 2008

University open days

  • University of Lincoln
    Mini Open Day at the Brayford Campus Undergraduate
    Wed, 19 Dec '18
  • University of East Anglia
    UEA Mini Open Day Undergraduate
    Fri, 4 Jan '19
  • Bournemouth University
    Undergraduate Mini Open Day Undergraduate
    Wed, 9 Jan '19
Poll
Did you get less than your required grades and still get into university?
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

Equations

Best calculators for A level Maths

Tips on which model to get

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.