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Math Help - 3 problems, trig identities

  1. #1
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    3 problems, trig identities

    prove:

    1. (1+cos x)/(sin x)+(sin x)/(1+cos x)=2csc x

    Solve:

    2. sin(a+b)

    given that: sin a=4/5 and tan b= -1

    3. cos(a+b)

    given that: cos a=4/5 and tan b= -1
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  2. #2
    MHF Contributor harish21's Avatar
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    \dfrac{1+\cos(x)}{\sin(x)}+\dfrac{\sin(x)}{1+\cos(  x)}

    =\dfrac{[(1+\cos(x))(1+\cos(x))]+[\sin(x)(\sin(x))]}{\sin(x)(1+\cos(x))}

    complete...
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  3. #3
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    2 more to go lol.
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  4. #4
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by Chris69 View Post
    2 more to go lol.
    How about you tell us how far you have gotten. Then we can assist you better.

    -Dan
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