Results 1 to 5 of 5

Math Help - cot 390 degrees

  1. #1
    Junior Member
    Joined
    Nov 2008
    From
    San Diego
    Posts
    40

    cot 390 degrees

    find the exact value of 390 degrees.

    can anyone help me figure out how to start this?thanks much
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by daydreembelievr View Post
    find the exact value of cot 390 degrees.

    can anyone help me figure out how to start this?thanks much
    I assume the red stuff was missing .....

    cot (390 degrees) = cot(30 degrees).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2008
    Posts
    6
    cot(390)
    = cot(30)
    = cos(30)/sin(30)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Nov 2008
    From
    San Diego
    Posts
    40
    why is it equal to cot 30 degrees? sorry if it is obvious.

    Is it because 390 - 360 = 30
    If so, it it -360 because 360 is a coterminal angle? thanks
    Last edited by daydreembelievr; November 6th 2008 at 02:18 PM.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by daydreembelievr View Post
    why is it equal to cot 30 degrees? sorry if it is obvious.

    Is it because 390 - 360 = 30
    If so, it it -360 because 360 is a coterminal angle? thanks
    Try showing 390 degrees on a unit circle. What do you notice?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. how come we know that i is 90 degrees or ~1.57 rad?
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: March 26th 2011, 03:17 PM
  2. Replies: 5
    Last Post: January 13th 2010, 11:50 AM
  3. Degrees
    Posted in the LaTeX Help Forum
    Replies: 2
    Last Post: May 29th 2009, 12:03 AM
  4. Replies: 2
    Last Post: April 6th 2009, 09:19 AM
  5. Sin(45 degrees) / Sec(110 degrees)
    Posted in the Trigonometry Forum
    Replies: 4
    Last Post: July 29th 2008, 09:50 PM

Search Tags


/mathhelpforum @mathhelpforum