Trigonometry

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cos 17pi/6 + tan 17pi/6

  • Trigonometry -

    Perhaps you might find it easier to think in degrees ?
    17π/6 radians = 510°
    which is coterminal with 150°

    cos 150° = - cos30° = -√3/2 , by CAST rule
    tan 150 = - tan30 = -1/√3

    so cos 17π/6 + tan 17π/6
    = -√3/2 - 1√3 , but 1/√3 = √3/3
    = -√3/2 - √3/3
    = ( -3√3 - 2√3)/6 = -5√3/6

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