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: What's the difference between sin^2(x) and sin(x^2)?

  1. Jan 25, 2012 #1
    1. The problem statement, all variables and given/known data

    what's the difference between sin^2(x) and sin(x^2)?

    2. Relevant equations

    3. The attempt at a solution

    I can't do sin^2(x) on the calculator. let's just use sin(25) as an example, what's the difference?
  2. jcsd
  3. Jan 25, 2012 #2


    Staff: Mentor

    first expression is sin(x) times sin(x) so you'd enter it as ( sin(x) ) ^ 2 and your calculator should be able to evaluate it.
  4. Jan 25, 2012 #3
    [itex]sin^{2}x = sinxsinx [/itex]
    The other 1 is just squaring the x not the whole function.

    Also on a side note,
    [itex]sinx+sinx = 2sinx[/itex]
  5. Jan 25, 2012 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Indeed. if x = 5, sin2(x) ≈ 0.919536, whereas sin(x2) ≈ -0.132352
  6. Jan 25, 2012 #5


    User Avatar
    Homework Helper
    Gold Member

    sin2x MEANS (sin x)2.

    Which you can calculate on your calculator.

    IMHO you are not the only one and not totally at fault to be confused - sin2x as far as I can see is a sort of mathematical slang, not strictly logical (so no wonder your calculator doesn't understand it either) which by its antiquity is let through and is universal - so there it is to get used to.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook