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TRIGONOMETRY HELP: sec^2 X - 1 / sec^2 X?

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sec^2 X - 1 / sec^2 X

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  • Favorite Answer

    (sec(x)^2 - 1) / sec(x)^2 =>

    tan(x)^2 / sec(x)^2 =>

    (sin(x)^2 / cos(x)^2) / (1 / cos(x)^2) =>

    sin(x)^2 / 1 =>

    sin(x)^2

  • 8 years ago

    if its (sec^2 X -1)/ sec^2 X ..

    Then this can be written as 1-(1/sec^2 X) due to the sec^2 X cancelling

    Then 1/sec^2 X = cos^2 X hence it can be written as 1-cos^2 X

    Now due too sin^2 X + cos^2 X = 1 then 1-cos^2 X = sin^2 X

    so... (sec^2 X -1)/ sec^2 X = Sin^2 X

    Source(s): A-level maths.. and going to do maths at uni
  • ?
    Lv 7
    8 years ago

    sec^2 x - 1 = tan^2 x

    tan^2 x / sec^2 x = tan^2 x * cos^2 x = sin^2 x = 1 - cos^2 x = 1 - 1/sec^2 x

  • Anonymous
    8 years ago

    ( sec^2 x - 1 ) / sec^2 x

    = (sec^2 x / sec^2 x) - (1 / sec^2 x )

    = 1 - cos^2 x

    = sin^2 x + cos^2 x - cos^2 x

    = Sin^2 x

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  • 8 years ago

    sec^2 X - 1 / sec^2 X

    = 1 -- 1/sec^2x

    = 1 -- cos^2x

    = sin^2x ANSWER

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