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Trig - Help with tan(arccos(x/3))

  1. Jul 7, 2005 #1
    Can anyone help asap?

    tan(arccos x/3)

  2. jcsd
  3. Jul 7, 2005 #2
    Draw a right triangle. If arccos x/3 = theta, draw that triangle.
  4. Jul 7, 2005 #3


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    if [tex]\theta=cos^{-1} \frac{x}{3}[/tex]

    then [tex]\frac{x}{3}[/tex] is the cosine of [tex]\theta[/tex]

    You can use the pythagorean theorem to find the sine of [tex]\theta[/tex]

    [tex]\cos^2 \theta + \sin^2 \theta = 1[/tex]

    The tangent of [tex]\theta[/tex] is [tex]\frac{sin \theta}{cos \theta}[/tex]
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