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Math Help - Cofunction identity

  1. #1
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    Cofunction identity

    Im trying to verify the identity cos (X-pi/2)= sin x

    Can someone please break down? Literally step by step. And indicate which identities r being used.

    Thank you.
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  2. #2
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    Re: Cofunction identity

    Cos (x-pi/2)=cos(x)cos(pi/2)+sin(x)sin(pi/2)

    Simplify.
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  3. #3
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    Re: Cofunction identity

    Yes, i figured as much using the sum and difference identity. Dont know what to do afterr that.
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  4. #4
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    Re: Cofunction identity

    Well, cos(pi/2)=0 and sin(pi/2)=1 so you end up with sin(x)=sin(x).
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  5. #5
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    Re: Cofunction identity

    Ohhhhhh....drat...didnt realize had to look at them individually, i was too bz just figuring out how to cancel each other out to get sin x alone. Thanks so much!
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