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    intergrate cos squared x...and is it the same as intergrating cosx squared? thanks
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    I always thought you *couldnt* integrate or differentiate cos^2x?

    It is an impossibility....
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    (Original post by samthemoron)
    I always thought you *couldnt* integrate or differentiate cos^2x?

    It is an impossibility....
    well that would solve a lot of things :p: especially as these notes were written on a friday morning after the thursday night before! :rolleyes:
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    cos2x=2cos²x-1

    =>cos²x=(1/2)cos2x+(1/2)

    So the integral of the LHS must equal the integral of the right hand side so integrate the RHS to get

    (1/4)sin2x+(1/2)x

    Newton.
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    Ok his idea sounds better then... where did you get that formula from (which course) ive never seen it before.

    btw if anyone does D1 then please answer some problems from my thread (Decision maths 1 (thursday))
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    (Original post by Newton)
    cos2x=2cos²x-1

    =>cos²x=(1/2)cos2x+(1/2)

    So the integral of the LHS must equal the integral of the right hand side so integrate the RHS to get

    (1/4)sin2x+(1/2)x

    Newton.
    wow, thanks newton lifesaver!! you know cos2A: what are the three forms it can go to?
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    (Original post by samthemoron)
    Ok his idea sounds better then... where did you get that formula from (which course) ive never seen it before.

    btw if anyone does D1 then please answer some problems from my thread (Decision maths 1 (thursday))
    aww cute, modest!
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    (Original post by strawberries)
    you know cos2A: what are the three forms it can go to?
    cos2x =

    2cos²x - 1
    or
    1-2sin²x
    or
    cos²x-sin²x
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    (Original post by prittstick)
    cos2x =

    2cos²x - 1
    or
    1-2sin²x
    or
    cos²x-sin²x
    thanx a lot aww peeps are helping me loads today
 
 
 
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