Cos 4 Degrees

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

What is cos 4°?

Answer

cos 4° ≈
0.9976

Angle in radians: 4° = π/45. The point of the angle is in quadrant I, where cosine is positive.

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

P(cos 4°, sin 4°) ≈ (0.9976, 0.0698)

xyOP

P(cos 4°, sin 4°) ≈ (0.9976, 0.0698)

Highlighted: the projection on the x-axis — cosine, x ≈ 0.9976.

All four functions of 4°
FunctionExact valueDecimal
sin 4°—≈ 0.0698
cos 4°—≈ 0.9976
tan 4°—≈ 0.0699
cot 4°—≈ 14.3007

See Also

Recalculate with different values ↑

Cosine of nearby angles

Anglecos
1°≈ 0.9998
2°≈ 0.9994
3°≈ 0.9986
4°≈ 0.9976
5°≈ 0.9962
6°≈ 0.9945
7°≈ 0.9925

FAQ

What is cos 4°?

cos 4° ≈ 0.9976

Why does cos 4° 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°. 4° is not, so no such exact form exists; the value is used as a decimal: cos 4° ≈ 0.9976.

Why does a calculator show −0.6536 for cos 4?

The calculator is in radian mode (RAD): it takes cos 4 as the cosine of 4 radians, cos 4 rad ≈ −0.6536. Switch it to degrees (DEG): cos 4° ≈ 0.9976. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also