Results 1 to 2 of 2

Math Help - Not sure what I'm supposed to do, "to find an expression for sin(3x) in terms of sin"

  1. #1
    Newbie
    Joined
    Mar 2010
    Posts
    5

    Question Not sure what I'm supposed to do, "to find an expression for sin(3x) in terms of sin"

    Part of question (from assignment): Use double-angle and addition formulŠ and other relations for trigonometrical functions to find an expression for sin(3x) in terms of sin x alone.

    I don't know what is meant by "to find an expression for sin(3x) in terms of sin x alone". I've found a working through of a very similar question but still don't get what is meant by it. I know how to "Use double-angle and addition formulŠ and other relations for trigonometrical functions" but I don't get what I'm supposed to be doing with them.

    This may seem stupid but I couldn't find an answer on google :/

    Would really appreciate some help with this!

    PS. This is actually for a university calculus paper but this seems like it would fit better here (sorry if it doesn't!).
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Jun 2009
    Posts
    806
    Thanks
    4
    The addition formula for sin is
    si(A + B) = sinAcosB + cosAsinB.
    Now spit 3x int (x + 2x) and then find
    sin(x + 2x) =........
    During simplification, try to replace cos terms by sin terms using trigonometric relations.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: April 24th 2011, 07:01 AM
  2. Replies: 1
    Last Post: October 25th 2010, 04:45 AM
  3. Replies: 2
    Last Post: October 14th 2009, 01:38 PM
  4. logic: expressing "or" in terms of "implies not"
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: September 29th 2007, 06:55 AM
  5. "Writing a Radical Quotient in Lowest Terms"
    Posted in the Algebra Forum
    Replies: 2
    Last Post: February 5th 2007, 07:09 PM

Search Tags


/mathhelpforum @mathhelpforum