Cos 3 Degrees

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

What is cos 3°?

Answer

cos 3° ≈
0.9986

Angle in radians: 3° = π/60. The point of the angle is in quadrant I, where cosine is positive.

≈ — rounded to 4 decimal places. An exact form of cos 3° in square roots exists, but it is unwieldy — nested radicals.

P(cos 3°, sin 3°) ≈ (0.9986, 0.0523)

xyOP

P(cos 3°, sin 3°) ≈ (0.9986, 0.0523)

Highlighted: the projection on the x-axis — cosine, x ≈ 0.9986.

All four functions of 3°
FunctionExact valueDecimal
sin 3°—≈ 0.0523
cos 3°—≈ 0.9986
tan 3°—≈ 0.0524
cot 3°—≈ 19.0811

See Also

Recalculate with different values ↑

Cosine of nearby angles

Anglecos
0°1
1°≈ 0.9998
2°≈ 0.9994
3°≈ 0.9986
4°≈ 0.9976
5°≈ 0.9962
6°≈ 0.9945

FAQ

What is cos 3°?

cos 3° ≈ 0.9986

Is there an exact value of cos 3°?

Yes: 3° 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: cos 3° ≈ 0.9986.

Why does a calculator show −0.9900 for cos 3?

The calculator is in radian mode (RAD): it takes cos 3 as the cosine of 3 radians, cos 3 rad ≈ −0.9900. Switch it to degrees (DEG): cos 3° ≈ 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