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    http://www.examsolutions.net/exampap...-january-2010/

    For q8 of this paper, can someone explain why cot2x is changed into cos2x/sin2x
    Why doesn't it work by changing it to 1/tan2x =0 ??

    Thanks
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    (Original post by coconut64)
    http://www.examsolutions.net/exampap...-january-2010/

    For q8 of this paper, can someone explain why cot2x is changed into cos2x/sin2x
    Why doesn't it work by changing it to 1/tan2x =0 ??

    Thanks
    Because 1 over something that varies will NEVER equal 0 therefore you cannot use that form. Tan is made up from cosine and sine at its base therefore you should ALWAYS decompose down to those 2 in these types of questions.
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    Multiply across by tan2x. You get an undefined equation.
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    That makes sense now, thanks guys
 
 
 
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