Cos 13 Degrees

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

What is cos 13°?

Answer

cos 13° ≈
0.9744

Angle in radians: 13° = 13π/180. The point of the angle is in quadrant I, where cosine is positive.

≈ — rounded to 4 decimal places. cos 13° can't be written with square roots: 13° is not a multiple of 3°.

P(cos 13°, sin 13°) ≈ (0.9744, 0.2250)

xyOP

P(cos 13°, sin 13°) ≈ (0.9744, 0.2250)

Highlighted: the projection on the x-axis — cosine, x ≈ 0.9744.

All four functions of 13°
FunctionExact valueDecimal
sin 13°—≈ 0.2250
cos 13°—≈ 0.9744
tan 13°—≈ 0.2309
cot 13°—≈ 4.3315

See Also

Recalculate with different values ↑

Cosine of nearby angles

Anglecos
10°≈ 0.9848
11°≈ 0.9816
12°≈ 0.9781
13°≈ 0.9744
14°≈ 0.9703
15°(√6 + √2)/4
16°≈ 0.9613

FAQ

What is cos 13°?

cos 13° ≈ 0.9744

Why does cos 13° 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°. 13° is not, so no such exact form exists; the value is used as a decimal: cos 13° ≈ 0.9744.

Why does a calculator show 0.9074 for cos 13?

The calculator is in radian mode (RAD): it takes cos 13 as the cosine of 13 radians, cos 13 rad ≈ 0.9074. Switch it to degrees (DEG): cos 13° ≈ 0.9744. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also