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    Cos 179 Degrees

    Sin, Cos, Tan, Cot of an Angle
    Function
    Angle (°)

    What is cos 179°?

    Answer

    cos 179° ≈
    −0.9998

    Angle in radians: 179° = 179π/180. The point of the angle is in quadrant II, where cosine is negative.

    ≈ — rounded to 4 decimal places. cos 179° can't be written with square roots: 179° is not a multiple of 3°.

    cos 179° = cos(180° − 1°) = −cos 1° ≈ −0.9998

    P(cos 179°, sin 179°) ≈ (−0.9998, 0.0175)

    xyOP

    P(cos 179°, sin 179°) ≈ (−0.9998, 0.0175)

    Highlighted: the projection on the x-axis — cosine, x ≈ −0.9998.

    All four functions of 179°
    FunctionExact valueDecimal
    sin 179°—≈ 0.0175
    cos 179°—≈ −0.9998
    tan 179°—≈ −0.0175
    cot 179°—≈ −57.2900

    Reference angle: cos 1° ≈ 0.9998

    See Also

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    https://calculat.io/en/number/trigonometry/cos--179Copy
    <a href="https://calculat.io/en/number/trigonometry/cos--179">Cos 179 Degrees: Cosine of 179° on the Unit Circle</a>Copy
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    Cos 179 Degrees: Cosine of 179° on the Unit Circle. cos 179° ≈ −0.9998. The cosine is the x-coordinate of the point at 179° on the unit circle; 179° reduces to 1°.
    https://calculat.io/en/number/trigonometry/cos--179/generated.jpgCopy

    Cosine of nearby angles

    Anglecos
    165°−(√6 + √2)/4
    167°≈ −0.9744
    175°≈ −0.9962
    179°≈ −0.9998
    180°−1
    195°−(√6 + √2)/4
    198°−√(10 + 2√5)/4
    Recalculate with different values ↑

    FAQ

    What is cos 179°?

    cos 179° ≈ −0.9998

    Why does cos 179° have no exact value?

    A trigonometric value of a whole number of degrees can be written with square roots only when the angle is a multiple of 3°. 179° is not, so no such exact form exists; the value is used as a decimal: cos 179° ≈ −0.9998.

    Why does a calculator show −0.9975 for cos 179?

    The calculator is in radian mode (RAD): it takes cos 179 as the cosine of 179 radians, cos 179 rad ≈ −0.9975. Switch it to degrees (DEG): cos 179° ≈ −0.9998. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

    See Also