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: Homework help!

  1. Oct 6, 2004 #1
    Can someone help me with this:cos^2x = 2cosxsinx?
    X E 0,360..
    I really haven`t understood this trigonomy stuff yet.. :yuck:
  2. jcsd
  3. Oct 6, 2004 #2

    matt grime

    User Avatar
    Science Advisor
    Homework Helper

    Did you see that sticky about posting homework?

    Hint: forget trig for now, and simplify

  4. Oct 6, 2004 #3
    Hi, Maria, I am Susan, :redface: What matt told you to do is something like this: :blushing:
    cosx(cosx-2sinx) =0
    cosx=0 OR tanx=1/2
    Last edited: Oct 6, 2004
  5. Oct 7, 2004 #4
    hi again

    Can you explain it to me a bit more?

    I need to understand the whole prosess, because I have to explain it to someone else on thursday.. I need 4 angles..
  6. Oct 7, 2004 #5


    User Avatar
    Science Advisor
    Homework Helper

    What you basically have is:

    [tex]a^2 = ab[/tex]

    You can wright this is:

    [tex]a^2 - ab = 0[/tex]

    [tex]a(a - b) = 0[/tex]

    This tells you that either [itex]a[/itex] is 0 or [itex]a - b[/itex] is 0, right? Well try and follow that procedure out with your trig functions.
  7. Oct 11, 2004 #6

    I got it right :smile: Thanks a lot
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook