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Math Help - Prove the following identities

  1. #1
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    Smile Prove the following identities

    I'm not sure the working step.

    tan x + tan y = sin(x + y) / cos x + tan y

    This my ans;

    LHS = sin x cos y + cos x sin y / cos x cos y
    = sin x + sin y
    = tan x + tan y
    = RHS
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  2. #2
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    Re: Prove the following identities

    Hey choi105.

    I think you may have copied this down wrong.

    Do you mean sin(x+y)/[cos(x) + tan(y)] instead?
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  3. #3
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    Re: Prove the following identities

    yup.
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  4. #4
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    Re: Prove the following identities

    The identity written is not true. Please recheck the question.
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  5. #5
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    Re: Prove the following identities

    sorry for typing error.
    The que: tan x + tan y = sin(x + y) / cos x + cos y
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  6. #6
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    Re: Prove the following identities

    Again it is wrong. Check the Dinominator.
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  7. #7
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    Re: Prove the following identities

    I think RHS would be having cosx cos y in the denominator.
    write tanx and tany in the form of sinx / cosx and siny/cosy. take LCM and use the formula for sum of angles the numerator and you have the result.
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