Results 1 to 3 of 3

Math Help - pi/9 is a root

  1. #1
    Junior Member
    Joined
    Jul 2008
    From
    near Xico, state of Veracruz, Mexico
    Posts
    26

    pi/9 is a root

    How do I show that \pi/9 is a root of 33*tan(x)^4-27*tan(x)^2-tan(x)^6+3?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie Catherine Morland's Avatar
    Joined
    Jul 2008
    Posts
    17
    Substitute into the formula and go from there.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jul 2008
    From
    near Xico, state of Veracruz, Mexico
    Posts
    26
    Thank you, Catherine. Yes putting t=Pi/9 in

    tan(3t) = (3tan(t)-tan(t)^3) / (1-3tan(t)^2)

    looks like it will do it.

    (for some reason your identity has
    disappeared, but in case someone reads this I put it
    back here so they would know what your reply was about).
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: December 5th 2011, 01:07 PM
  2. square root + cube root of a number
    Posted in the Algebra Forum
    Replies: 2
    Last Post: December 5th 2010, 10:35 AM
  3. Replies: 2
    Last Post: April 6th 2009, 03:51 AM
  4. Replies: 12
    Last Post: November 22nd 2008, 12:41 PM
  5. Replies: 1
    Last Post: March 29th 2008, 11:11 AM

Search Tags


/mathhelpforum @mathhelpforum