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Homework Help: Need help with a trigonometric expression

  1. Dec 29, 2017 #1
    • Member warned that posts must include an effort
    1. The problem statement, all variables and given/known data
    Just a simple problem, I need to take the expression##\frac 1 2 (sin(2x)+1)## and show it is equivalent to ##sin^2(x+\frac \pi 4)##, and I cant seem to manage to find the way to do so, so I would appreciate some insight.

    2. Relevant equations
    N/A

    3. The attempt at a solution
    Effectively messing around with the trigonometric identities to no avail.
     
  2. jcsd
  3. Dec 29, 2017 #2

    BvU

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    You will need some relevant equations... N/A doesn't get you any further

    And 'dunno' doesn't qualify as an attempt at solution.
     
  4. Dec 29, 2017 #3

    BvU

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    I do intend to help you with this really very simple problem, but I have to adhere to the rules (see PF guidelines ).
    For starters: what do you get when you write out both in terms of ##\ \sin x\ ## and ##\ \cos x \ ## ?
     
  5. Dec 29, 2017 #4
    I guess I needed to write some identities there, sorry.
    Following your comment I used sin (a + b) = sin a.cos b + sin b.cos a and got the wanted expression, thanks for the help.
     
  6. Dec 29, 2017 #5

    scottdave

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