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    Cot 21 Degrees

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

    What is cot 21°?

    Answer

    cot 21° ≈
    2.6051

    Angle in radians: 21° = 7π/60. The point of the angle is in quadrant I, where cotangent is positive.

    ≈ — rounded to 4 decimal places. An exact form of cot 21° in square roots exists, but it is unwieldy — nested radicals.

    cot 21° = cos 21° / sin 21° ≈ 2.6051

    xyOP

    P(cos 21°, sin 21°) ≈ (0.9336, 0.3584)

    C(cot 21°, 1) ≈ (2.6051, 1) — where line OP meets the line y = 1; C is beyond the drawing, the arrow points to it.

    All four functions of 21°
    FunctionExact valueDecimal
    sin 21°—≈ 0.3584
    cos 21°—≈ 0.9336
    tan 21°—≈ 0.3839
    cot 21°—≈ 2.6051

    See Also

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    https://calculat.io/en/number/trigonometry/cot--21Copy
    <a href="https://calculat.io/en/number/trigonometry/cot--21">Cot 21 Degrees: Cotangent of 21° on the Unit Circle</a>Copy
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    Cot 21 Degrees: Cotangent of 21° on the Unit Circle. cot 21° ≈ 2.6051. The cotangent is the ratio x/y of the point at 21° on the unit circle.
    https://calculat.io/en/number/trigonometry/cot--21/generated.jpgCopy

    Cotangent of nearby angles

    Anglecot
    18°√(5 + 2√5)
    19°≈ 2.9042
    20°≈ 2.7475
    21°≈ 2.6051
    22°≈ 2.4751
    23°≈ 2.3559
    24°≈ 2.2460
    Recalculate with different values ↑

    FAQ

    What is cot 21°?

    cot 21° ≈ 2.6051

    Is there an exact value of cot 21°?

    Yes: 21° is a multiple of 3°, and the values of such angles can be written with square roots — but the expression is unwieldy, with nested radicals built from the values of 18° and 15° (3° = 18° − 15°). In practice the decimal is used: cot 21° ≈ 2.6051.

    Why does a calculator show −0.6547 for cot 21?

    The calculator is in radian mode (RAD): it takes cot 21 as the cotangent of 21 radians, cot 21 rad ≈ −0.6547. Switch it to degrees (DEG): cot 21° ≈ 2.6051. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

    See Also