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    Sin 87 Degrees

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

    What is sin 87°?

    Answer

    sin 87° ≈
    0.9986

    Angle in radians: 87° = 29π/60. The point of the angle is in quadrant I, where sine is positive.

    ≈ — rounded to 4 decimal places. An exact form of sin 87° in square roots exists, but it is unwieldy — nested radicals.

    P(cos 87°, sin 87°) ≈ (0.0523, 0.9986)

    xyOP

    P(cos 87°, sin 87°) ≈ (0.0523, 0.9986)

    Highlighted: the projection on the y-axis — sine, y ≈ 0.9986.

    All four functions of 87°
    FunctionExact valueDecimal
    sin 87°—≈ 0.9986
    cos 87°—≈ 0.0523
    tan 87°—≈ 19.0811
    cot 87°—≈ 0.0524

    See Also

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    <a href="https://calculat.io/en/number/trigonometry/sin--87">Sin 87 Degrees: Sine of 87° on the Unit Circle - Calculatio</a>Copy
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    Sin 87 Degrees: Sine of 87° on the Unit Circle. sin 87° ≈ 0.9986. The sine is the y-coordinate of the point at 87° on the unit circle.
    https://calculat.io/en/number/trigonometry/sin--87/generated.jpgCopy

    Sine of nearby angles

    Anglesin
    84°≈ 0.9945
    85°≈ 0.9962
    86°≈ 0.9976
    87°≈ 0.9986
    88°≈ 0.9994
    89°≈ 0.9998
    90°1
    Recalculate with different values ↑

    FAQ

    What is sin 87°?

    sin 87° ≈ 0.9986

    Is there an exact value of sin 87°?

    Yes: 87° 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: sin 87° ≈ 0.9986.

    Why does a calculator show −0.8218 for sin 87?

    The calculator is in radian mode (RAD): it takes sin 87 as the sine of 87 radians, sin 87 rad ≈ −0.8218. Switch it to degrees (DEG): sin 87° ≈ 0.9986. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

    See Also