Results 1 to 2 of 2

Math Help - Finding solutions

  1. #1
    Member
    Joined
    Nov 2008
    Posts
    103

    Finding solutions

    Find a solution to = -10/17 in the interval [, ] correct to two decimal places.

    How would you solve this? Cheers.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Dec 2008
    Posts
    152
    <br /> <br />
cos x = (-\frac{10}{17})<br />
    <br />
x_{1} = 126.03^0 + k2\Pi<br />
    <br />
x_{2} = 233.97^0 + k2\Pi<br />

    <br />
19\Pi \leq x_{1,2} + k2\Pi \leq 20\Pi  \Rightarrow 3420^0 \leq x_{1,2} + k \times 360^0 \leq 3600^0<br />

    from that you know that k is 9 because the solution needs to be in the  [19\Pi, 20\Pi] interval.

    if k = 9
    then

    <br />
k2\Pi = 9 \times 2 \times 180^0 = 3240^0<br />

     3240^0 + x_{1} \leq 19\Pi
    20\Pi \geq 3240^0  + x_{2} \geq 19\Pi

    x_{2} = 233,97^0 is the solution.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finding solutions
    Posted in the Advanced Algebra Forum
    Replies: 9
    Last Post: March 17th 2010, 07:50 PM
  2. finding solutions
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: April 27th 2009, 05:43 PM
  3. Finding Solutions
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: April 9th 2009, 03:43 PM
  4. finding solutions
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: April 7th 2009, 08:35 AM
  5. Need help finding solutions
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: June 30th 2008, 03:25 PM

Search Tags


/mathhelpforum @mathhelpforum