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    Cos 570 Degrees

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

    What is cos 570°?

    Answer

    cos 570° =
    −√3/2 ≈ −0.8660

    Angle in radians: 570° = 19π/6. 570° = 360° + 210° — a full turn plus 210°, quadrant III, where cosine is negative.

    ≈ — rounded to 4 decimal places.

    cos 570° = cos(570° − 360°) = cos 210°

    cos 210° = cos(180° + 30°) = −cos 30° = −√3/2

    P(cos 570°, sin 570°) = (−√3/2, −1/2)

    Half of an equilateral triangle with side 1: the hypotenuse is 1 and the leg opposite 30° is 1/2.

    cos 30° = √(1 − 1/4) = √3/2

    xyOP

    P(cos 570°, sin 570°) ≈ (−0.8660, −0.5)

    Highlighted: the projection on the x-axis — cosine, x ≈ −0.8660.

    +1 turn: the drawing shows 210°.

    All four functions of 570°
    FunctionExact valueDecimal
    sin 570°−1/2−0.5
    cos 570°−√3/2≈ −0.8660
    tan 570°√3/3≈ 0.5774
    cot 570°√3≈ 1.7321

    Reference angle: cos 30° = √3/2

    See Also

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    https://calculat.io/en/number/trigonometry/cos--570Copy
    <a href="https://calculat.io/en/number/trigonometry/cos--570">Cos 570 Degrees: Cosine of 570° on the Unit Circle</a>Copy
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    Cos 570 Degrees: Cosine of 570° on the Unit Circle. cos 570° = −√3/2 ≈ −0.8660. The cosine is the x-coordinate of the point at 570° on the unit circle; 570° reduces to 30°.
    https://calculat.io/en/number/trigonometry/cos--570/generated.jpgCopy

    Cosine of nearby angles

    Anglecos
    390°√3/2
    400°≈ 0.7660
    450°0
    540°−1
    570°−√3/2
    690°√3/2
    720°1
    Recalculate with different values ↑

    FAQ

    What is cos 570°?

    cos 570° = −√3/2 ≈ −0.8660

    How to remember sin 30°, sin 45° and sin 60°?

    Write them as √1/2, √2/2, √3/2: sin 30° = 1/2, sin 45° = √2/2, sin 60° = √3/2. Cosines are the same numbers in reverse order: cos 30° = √3/2, cos 45° = √2/2, cos 60° = 1/2; tan = sin / cos and cot = cos / sin. Here: cos 570° = −√3/2 ≈ −0.8660.

    Why does a calculator show −0.1978 for cos 570?

    The calculator is in radian mode (RAD): it takes cos 570 as the cosine of 570 radians, cos 570 rad ≈ −0.1978. Switch it to degrees (DEG): cos 570° = −√3/2 ≈ −0.8660. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

    See Also