1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Finding roots of this trig eqn

  1. Nov 19, 2013 #1

    utkarshakash

    User Avatar
    Gold Member

    1. The problem statement, all variables and given/known data
    If [sinx]+[√2 cosx]=-3, x belongs to [0,2∏] (where [.] denotes the greatest integer function) then x belongs to
    1)[5∏/4,2∏]
    2)(5∏/4,2∏)
    3)(∏,5∏/4)
    4)[∏,5∏/4]

    3. The attempt at a solution

    If I put x=5∏/4, LHS=-2 which does not satisfy. 2∏ and ∏ also does not satisfy.So the answer must be either 2) or 3). Is there any better way other than putting the values one by one and checking?
     
  2. jcsd
  3. Nov 19, 2013 #2

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    What are the lowest possible values of the two terms on the left? How can they add to -3?
     
  4. Nov 20, 2013 #3

    utkarshakash

    User Avatar
    Gold Member

    That was helpful. Thanks!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Finding roots of this trig eqn
  1. Finding root (Replies: 10)

Loading...