Cos 10 Degrees

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

What is cos 10°?

Answer

cos 10° ≈
0.9848

Angle in radians: 10° = π/18. The point of the angle is in quadrant I, where cosine is positive.

≈ — rounded to 4 decimal places. cos 10° can't be written with square roots: 10° is not a multiple of 3°.

P(cos 10°, sin 10°) ≈ (0.9848, 0.1736)

xyOP

P(cos 10°, sin 10°) ≈ (0.9848, 0.1736)

Highlighted: the projection on the x-axis — cosine, x ≈ 0.9848.

All four functions of 10°
FunctionExact valueDecimal
sin 10°—≈ 0.1736
cos 10°—≈ 0.9848
tan 10°—≈ 0.1763
cot 10°—≈ 5.6713

See Also

Recalculate with different values ↑

Cosine of nearby angles

Anglecos
7°≈ 0.9925
8°≈ 0.9903
9°≈ 0.9877
10°≈ 0.9848
11°≈ 0.9816
12°≈ 0.9781
13°≈ 0.9744

FAQ

What is cos 10°?

cos 10° ≈ 0.9848

Why does cos 10° 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°. 10° is not, so no such exact form exists; the value is used as a decimal: cos 10° ≈ 0.9848.

Why does a calculator show −0.8391 for cos 10?

The calculator is in radian mode (RAD): it takes cos 10 as the cosine of 10 radians, cos 10 rad ≈ −0.8391. Switch it to degrees (DEG): cos 10° ≈ 0.9848. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also