Results 1 to 3 of 3

Math Help - isolating and solving for a variable

  1. #1
    Newbie
    Joined
    Feb 2011
    Posts
    2

    isolating and solving for a variable

    This is a basic algebra question set in a physics question. Yes I know I should have learned this a long time ago but I played cards through math class in middle school and it's finally catching up, thank you very much.

    My question:
    in my physics book they rearrange an equation from

    this

    (sin80/sin10)*T*cos10 - T*cos80 - W = 0

    to

    T = W / [(sin80/sin10)cos10 - cos80]

    How?

    I generally understand whats going on here, the W can be "added" to the other side and then divided by the various trig function however I don't know how I ended up with just one T on the left side. My instinct would be to try and combine them (2T or -2T?) but that's clearly not what happened.

    suggestions? Thanks for your time.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,939
    Thanks
    338
    Awards
    1
    Quote Originally Posted by Wowbagger View Post
    (sin80/sin10)*T*cos10 - T*cos80 - W = 0
    Isolate the W:
    (sin80/sin10)*T*cos10 - T*cos80 = W

    Now notice that the LHS has a common T. Factor this T:
    [ (sin80/sin10)*cos10 - cos80 ]*T = W

    Now, (sin80/sin10)*cos10 - cos80 is just a number. Divide both sides by it:
    T = W/[ (sin80/sin10)*cos10 - cos80 ]

    -Dan
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Feb 2011
    Posts
    2
    Very cool, thanks so much.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Isolating a Variable
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: October 26th 2010, 04:12 PM
  2. Isolating a variable
    Posted in the Algebra Forum
    Replies: 9
    Last Post: October 10th 2010, 08:44 PM
  3. Isolating a Variable
    Posted in the Calculus Forum
    Replies: 7
    Last Post: April 12th 2010, 06:21 PM
  4. Help Isolating a Variable
    Posted in the Calculus Forum
    Replies: 1
    Last Post: November 2nd 2009, 03:10 PM
  5. Isolating a variable in the numerator
    Posted in the Algebra Forum
    Replies: 3
    Last Post: July 7th 2007, 04:19 PM

Search Tags


/mathhelpforum @mathhelpforum