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Homework Help: Major h.w help needed tri functions derivatives =\

  1. Jun 27, 2007 #1
    Hey guys having major trouble with these 2 questions, i have a screen shot of the questions and my work , much easier to understand then me typing it in here. thanks soo much for helping !

  2. jcsd
  3. Jun 27, 2007 #2
    You have the right idea, but you just need to be watch out for a few small things.

    First of all:
    Remember the Chain Rule:
    \frac{d}{dx}(sin(2x)) = 2cos(2x)

    Be careful with your minus signs, especially with going from step 2 to step 3.

    Once you get all that out of the way, go through your trig identities and see if you can't simplify it any (http://www.sosmath.com/trig/Trig5/trig5/trig5.html if you need a good list of them).

    - Jason
  4. Jun 27, 2007 #3


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    You have an error in the derivitave of sin(2x) and cos(2x). Use the chain rule, you are missing a factor of 2. Continue.
  5. Jun 27, 2007 #4
    ok so basically for my second line i was only missing a 2 for dsin(2x)/dx and dcos(2x)/dx then i can go ahead and simplift using tri propertys? did i mix something up cause i dont see any that are obvious

    and secondly, did anyone check out the second question i had on that page, did i do the first and second derivative right?
  6. Jun 27, 2007 #5
    The second one matches what I got.
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