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Math Help - Need help getting started identities.

  1. #1
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    Need help getting started identities.

    Hey guys,
    I need some help getting started with proving this identity problem. Everytime I get started I feel like I am just making it uglier
    ((1 +sin theta)/(1-sin theta))-((1-sin theta)/(1+sin theta)=4*tan theta*sec theta

    Thanks for your help!

    ~Nikki
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  2. #2
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    Re: Need help getting started identities.

    I'll write x instead of theta
    Put the left hand side onto a common denominator of (1-sinx)(1+sinx) and simplify your numerator.
    Note this common denominator will also simplify to 1-sin^2x which= cos^2x
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  3. #3
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    Re: Need help getting started identities.

    Starting with the LHS get a common denominator, namely (1-\sin\theta)(1+\sin\theta).

    Expand and simplify the numerator and you should be done.

    Post again if you're still stuck.
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  4. #4
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    Re: Need help getting started identities.

    Thank you very much! I think I got it, I ended up with -(4sinx)/(cosx)^2=4tanx*secx
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  5. #5
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    Re: Need help getting started identities.

    So I would do the same thing for this problem right? find the common denominator on the LHS? ((sinx+cosx)/sinx) - ((cosx-sinx)/cosx)=secx*cscx
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