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Math sine homework

  1. Mar 15, 2004 #1
    Can someone help me with my homework?
    It would be great if I could get it back within the next 10 hours.
    The sooner the better though. Thanks to anyone who can do these for me.
    Working out for first 3 questions would be appreciated.
    Fourth question only requires multiple choice answer.

    1) If sin(x) = 3/5 and sin(y) = 24/25 and, pi/2 < y < x < pi, find the value of:
    a) cos(2x)
    b) sin(2x)
    c) sin(x-y)

    2) Simplify
    a) [sin(x)/sin(x)] - [cos(3x)/cos(x)]
    b) sin(x)cos(x)cos(2x)

    3) Prove that tan(pi/4 + x) - tan(pi/4 - x) = 2tan(2x)

    4) If tan(x) = 4/3 and tan(y) = 5/12, then the value of tan(x+y) is:
    Multiple Choice:
    A. sin(2x)
    B. cos(2x)
    C. sin(4x)
    D. 25/24
  2. jcsd
  3. Mar 15, 2004 #2
    Next time, please post this only once in one forum, the homework help forum.

    When you calculate the sine of an angle, you're dividing the opposite side by the hypotenuse. So, keeping that in mind, here's a little hint:

    [tex]\sin{x} = \frac{3}{5} = \frac{\textrm{opposite}}{\textrm{hypotenuse}}[/tex]

    So what do you think the opposite and hypotenuse sides might be?

    #4 is handled similarly.

    #'s 2 and 3 just require you to use a bunch of formulas. I'm certain you were given plenty in your class, so why don't you look at those?

  4. Mar 15, 2004 #3
    Sorry bout that, i know, all my fault, sorry.

    its more like i am lazy, lol.
    i'll get it done, thanx for bossing me, and giving me an incentive to do it now.
    lol, ta agen.

    Code (Text):
    I(laziness) = You/X, X>1
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