Cos 39 Degrees
Sin, Cos, Tan, Cot of an Angle
What is cos 39°?
Answer
cos 39° ≈
0.7771
Angle in radians: 39° = 13π/60. The point of the angle is in quadrant I, where cosine is positive.
≈ — rounded to 4 decimal places. An exact form of cos 39° in square roots exists, but it is unwieldy — nested radicals.
P(cos 39°, sin 39°) ≈ (0.7771, 0.6293)
P(cos 39°, sin 39°) ≈ (0.7771, 0.6293)
Highlighted: the projection on the x-axis — cosine, x ≈ 0.7771.
See Also
- Arcsin, Arccos, Arctan, Arccot - The angle from the value of its sine, cosine, tangent or cotangent: exact in degrees and π, with the check and the unit circle
- Square Root Calculator - Calculate the square root of any number
- Simplify Square Root Calculator - Write any square root in simplest radical form, step by step
- Geometry Formulas: Area, Volume, Perimeter - The formula for every standard shape, where it comes from, and worked examples
Cosine of nearby angles
FAQ
What is cos 39°?
cos 39° ≈ 0.7771
Is there an exact value of cos 39°?
Yes: 39° 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 39° ≈ 0.7771.
Why does a calculator show 0.2666 for cos 39?
The calculator is in radian mode (RAD): it takes cos 39 as the cosine of 39 radians, cos 39 rad ≈ 0.2666. Switch it to degrees (DEG): cos 39° ≈ 0.7771. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.
See Also
- Cos 29 Degrees: Cosine of 29° on the Unit Circle
- Cos 30 Degrees: Cosine of 30° on the Unit Circle
- Cos 31 Degrees: Cosine of 31° on the Unit Circle
- Cos 32 Degrees: Cosine of 32° on the Unit Circle
- Cos 33 Degrees: Cosine of 33° on the Unit Circle
- Cos 34 Degrees: Cosine of 34° on the Unit Circle
- Cos 35 Degrees: Cosine of 35° on the Unit Circle
- Cos 36 Degrees: Cosine of 36° on the Unit Circle
- Cos 37 Degrees: Cosine of 37° on the Unit Circle
- Cos 38 Degrees: Cosine of 38° on the Unit Circle
- Cos 40 Degrees: Cosine of 40° on the Unit Circle
- Cos 41 Degrees: Cosine of 41° on the Unit Circle
- Cos 42 Degrees: Cosine of 42° on the Unit Circle
- Cos 43 Degrees: Cosine of 43° on the Unit Circle
- Cos 44 Degrees: Cosine of 44° on the Unit Circle
- Cos 45 Degrees: Cosine of 45° on the Unit Circle
- Cos 46 Degrees: Cosine of 46° on the Unit Circle
- Cos 47 Degrees: Cosine of 47° on the Unit Circle
- Cos 48 Degrees: Cosine of 48° on the Unit Circle
- Cos 49 Degrees: Cosine of 49° on the Unit Circle
- Косинус 39 градусов (cos 39°) на единичной окружности
- Coseno de 39 grados (cos 39°) en el círculo unitario
- Cosseno de 39 graus (cos 39°) no ciclo trigonométrico