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    Cos 98 Degrees

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

    What is cos 98°?

    Answer

    cos 98° ≈
    −0.1392

    Angle in radians: 98° = 49π/90. The point of the angle is in quadrant II, where cosine is negative.

    ≈ — rounded to 4 decimal places. cos 98° can't be written with square roots: 98° is not a multiple of 3°.

    cos 98° = cos(180° − 82°) = −cos 82° ≈ −0.1392

    P(cos 98°, sin 98°) ≈ (−0.1392, 0.9903)

    xyOP

    P(cos 98°, sin 98°) ≈ (−0.1392, 0.9903)

    Highlighted: the projection on the x-axis — cosine, x ≈ −0.1392.

    All four functions of 98°
    FunctionExact valueDecimal
    sin 98°—≈ 0.9903
    cos 98°—≈ −0.1392
    tan 98°—≈ −7.1154
    cot 98°—≈ −0.1405

    Reference angle: cos 82° ≈ 0.1392

    See Also

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    https://calculat.io/en/number/trigonometry/cos--98Copy
    <a href="https://calculat.io/en/number/trigonometry/cos--98">Cos 98 Degrees: Cosine of 98° on the Unit Circle</a>Copy
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    Cos 98 Degrees: Cosine of 98° on the Unit Circle. cos 98° ≈ −0.1392. The cosine is the x-coordinate of the point at 98° on the unit circle; 98° reduces to 82°.
    https://calculat.io/en/number/trigonometry/cos--98/generated.jpgCopy

    Cosine of nearby angles

    Anglecos
    89°≈ 0.0175
    90°0
    97°≈ −0.1219
    98°≈ −0.1392
    100°≈ −0.1736
    101°≈ −0.1908
    105°−(√6 − √2)/4
    Recalculate with different values ↑

    FAQ

    What is cos 98°?

    cos 98° ≈ −0.1392

    Why does cos 98° 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°. 98° is not, so no such exact form exists; the value is used as a decimal: cos 98° ≈ −0.1392.

    Why does a calculator show −0.8193 for cos 98?

    The calculator is in radian mode (RAD): it takes cos 98 as the cosine of 98 radians, cos 98 rad ≈ −0.8193. Switch it to degrees (DEG): cos 98° ≈ −0.1392. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

    See Also