1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Calculator, Q 17 - what it getting at

  1. Apr 7, 2007 #1
    What is this question going for. I can identify that OTA is a right angled triangle..... Where do I go from
  2. jcsd
  3. Apr 7, 2007 #2


    User Avatar
    Staff Emeritus
    Science Advisor

  4. Apr 7, 2007 #3
    [tex](x+8)(x+8) = x^{2} + (x+5)(x+5)[/tex]

    [tex]x ^ {2} + 16x + 64 = x^4+10x+25[/tex]

    take LHS from RHS

    [tex]x^{2} - 6x - 39 = 0[/tex]

    but how did you know to use pythagerous?
  5. Apr 7, 2007 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    What relationships DO you know hold for right-angled triangles that might come in handy?
  6. Apr 7, 2007 #5


    User Avatar
    Staff Emeritus
    Science Advisor

    Sorry, one correction to your second line.

    [tex]x ^ {2} + 16x + 64 = 2x^2+10x+25[/tex]

    Well, you did the hard part; spotting that it was a right angled triangle. Pythagoras' theorem holds for right angled triangles, and is a relationship relating the squares of the sides. Since the solution contains an x^2, this is quite a big hint as to what you should use.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook