Results 1 to 5 of 5

Math Help - solving for theta

  1. #1
    Newbie
    Joined
    Nov 2009
    Posts
    9

    solving for theta

    Can someone just get me started on this problem? Thanks.

    2cos(theta)-sin2(theta)=0

    I tried to substitute 2sin(theta)cos(theta) for the sin2(theta), but that didn't really get me anywhere.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    2\cos(\theta)-\sin(2\theta)=0

     2\cos(\theta)-2\sin(\theta)\cos(\theta)=0

    now factor and divide

     2\cos(\theta)(1-\sin(\theta))=0

     1-\sin(\theta)=0

     \sin(\theta)=1

    Can you solve it now?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Nov 2009
    Posts
    9
    How did you get from the second line to the 3rd line?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    I took out 2\cos(\theta) as a common factor in the left hand side.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Nov 2009
    Posts
    9
    Got it now. Thanks!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Solving for theta
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: June 12th 2011, 06:50 AM
  2. Solving for theta
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: June 2nd 2011, 02:35 AM
  3. Replies: 3
    Last Post: July 8th 2010, 02:13 PM
  4. Replies: 2
    Last Post: March 29th 2010, 06:38 AM
  5. Solving for theta
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: January 19th 2010, 02:14 PM

Search Tags


/mathhelpforum @mathhelpforum