Geometryy

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given that sec theta = radical13/whole number 3, and csctheta<0 find sin theta using the 2different methods;

1)using the "x-y-r" definition


2) using identities only

  • Geometryy -

    Timmy, Ryland, Cobra, Jaime -- you must be having an identity crisis tonight.

    Please use the same name for all of your posts.

  • Geometryy -

    given sec Ø = √13/3 ---> cosØ = 3/√13
    also cscØ < 0 ---> sinØ < 0
    Ø must be in quadr IV
    so x = 3 , r = √13

    x^2 + y^2 = r^2
    9 + y^2 = 13
    y^2 = 4
    y = ± 2 , but in IV y = -2

    sin Ø = -2/√13

    2) you should know that
    sin^2Ø + cos^2Ø = 1
    sin^2Ø + 9/13 = 1
    sin^2Ø = 4/13
    sinØ = 2/√13 , but we know that Ø is in IV, where the sine is negative, so
    sinØ = -2/√13

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