Results 1 to 2 of 2

Thread: cotangent

  1. #1
    Newbie
    Joined
    Sep 2008
    Posts
    19

    cotangent

    Can I distribute cotangent here???

    cot(Arccot 3 + Arccot 7 + Arccot 15 + Arccot 21)

    Can you please show the solution???
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Oct 2007
    From
    London / Cambridge
    Posts
    591
    Quote Originally Posted by maeca View Post
    Can I distribute cotangent here???

    cot(Arccot 3 + Arccot 7 + Arccot 15 + Arccot 21)

    Can you please show the solution???
    nope you cannot distribute the cotangent here, you will need to use the double angle formula here (several times)

    first note that \cot ( A + B ) = \frac{\cot A \cot B  - 1}{\cot A + \cot B}

    so your thing becomes

    \cot( accot 3 + acot 7 + acot 15 + acot 21) = \frac{\cot (accot 3 + acot 7) \cot (acot 15 + acot 21) - 1}{\cot (accot 3 + acot 7)  + \cot (acot 15 + acot 21)}<br />

    can you finish this off ?

    Bobak
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Calculating the value for cotangent.
    Posted in the Trigonometry Forum
    Replies: 6
    Last Post: Jun 30th 2011, 11:56 AM
  2. Cotangent pi/2
    Posted in the Geometry Forum
    Replies: 2
    Last Post: Jul 26th 2009, 01:21 PM
  3. Help with hyperbolic cotangent
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: Jun 25th 2008, 06:41 PM
  4. tangent and cotangent
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: Feb 18th 2008, 01:52 PM
  5. Replies: 2
    Last Post: Oct 26th 2007, 10:39 AM

Search Tags


/mathhelpforum @mathhelpforum