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Math Help - 3 quick question's on Identities

  1. #1
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    3 quick question's on Identities

    1)How would you verify this numerically?
    there is no given value of x so Im confused just use a calculator?
    (pi/2+x)=sin(pi/2-x)

    2)even when you get a given value of x I get confused like
    cos(pi-x)=-cosx
    when x=2.9

    3)also if you are given a list of possible identities and are asked to say which ones are and which ones arent how do you do that? Just sketch it, I mean it worked for me but if you have a easier way Id love any input.
    example

    tan-x=tanx
    tan-x=-tanx
    sin(pi/2+x)=cosx
    sin(pi/2-x)=cosx
    thanks.
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  2. #2
    No one in Particular VonNemo19's Avatar
    Joined
    Apr 2009
    From
    Detroit, MI
    Posts
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    I'm not too sure about what you are asking, but maybe this will help you along your way.




    Co-Function Identities



    Even-Odd Identities



    Visualizing what is happening on the graph with the unit circle situated with its center at the origin while an angle is rotating around and x and y constantly changing helps me to understand these identities.

    I know it's confusing, but you'll get it.
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