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    Show that cos2x/cosx+ sixx = cosx-sinx. I know trig identities need to be used, but i do not know how to get the answer at all.
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    (Original post by stefl14)
    Show that cos2x/cosx+ sixx = cosx-sinx. I know trig identities need to be used, but i do not know how to get the answer at all.
    Focus on the left hand side first.

    Try replacing the Cos2x with some trig identities.
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    well yes i get (cosx)^2-(sinx)^2/cos x + sin x but not quite sure why this is cos x - sin x
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    (Original post by stefl14)
    well yes i get (cosx)^2-(sinx)^2/cos x + sin x but not quite sure why this is cos x - sin x
    Factorise the numerator -- it's the difference of two squares.
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    anyone?
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    oke thanks, I need to recognise this stuff more easily...
 
 
 
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Updated: April 2, 2011
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