Results 1 to 7 of 7

Math Help - Write the trigonometric expression as an algebraic expression in U

  1. #1
    Member
    Joined
    Oct 2011
    Posts
    86
    Thanks
    2

    Write the trigonometric expression as an algebraic expression in U

    cos(arctan U)

    I seriously had this down until my teacher stopped using numbers...
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,675
    Thanks
    1618
    Awards
    1

    Re: Write the trigonometric expression as an algebraic expression in U

    Quote Originally Posted by Nervous View Post
    cos(arctan U)
    Let \theta=\arctan(U), then \tan(\theta)=U.
    So what is \cos(\theta)=~?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Oct 2011
    Posts
    86
    Thanks
    2

    Re: Write the trigonometric expression as an algebraic expression in U

    Cos(Theta) = cos(arctan(U))
    Cos(Tan(theta))= Cos(U)
    ArcCos(Tan(theta))=U

    Yes?
    Last edited by Nervous; October 6th 2011 at 01:13 PM.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,675
    Thanks
    1618
    Awards
    1

    Re: Write the trigonometric expression as an algebraic expression in U

    Quote Originally Posted by Nervous View Post
    Cos(Theta) = cos(arctan(U))
    But that doesn't get me anywhere...?
    Oh come on. THINK!
    If \tan(\theta)=3 what \cos(\theta)=~?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Oct 2011
    Posts
    86
    Thanks
    2

    Re: Write the trigonometric expression as an algebraic expression in U

    Where does 3 come from? And I editted my post since you replied
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,675
    Thanks
    1618
    Awards
    1

    Re: Write the trigonometric expression as an algebraic expression in U

    Quote Originally Posted by Nervous View Post
    Where does 3 come from?
    Well, in the OP you complained about not having numbers.

    Are you saying that if someone tells you that \tan(\theta)=3 that you cannot tell us what value \cos(\theta) has.

    If you cannot, then no wonder you don't know how do this question.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5

    Re: Write the trigonometric expression as an algebraic expression in U

    Quote Originally Posted by Nervous View Post
    Where does 3 come from? And I editted my post since you replied
    Where the 3 comes from is that Plato is giving you a concrete example of the general question \tan(\theta) = u, ~ \cos(\theta) = ? to try and guide you to answering the general question. You are meant to realise that.

    Answer Plato's question ( \tan(\theta) = 3, ~ \cos(\theta) = ?) and then consider how you might use it as a guide to answering \tan(\theta) = u, ~ \cos(\theta) = ?

    Also, please don't edit posts after getting replies. For obvious reasons it just creates confusion.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: April 10th 2011, 06:26 PM
  2. Write Algebraic Expression in x
    Posted in the Algebra Forum
    Replies: 4
    Last Post: October 6th 2010, 03:27 PM
  3. How do I write an algebraic expression?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 17th 2010, 04:51 AM
  4. write algebraic expression as a trig function
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: April 27th 2009, 05:50 PM
  5. Trigonometric Expression As Algebraic
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: August 28th 2008, 02:59 PM

Search Tags


/mathhelpforum @mathhelpforum