Cos 300 Degrees

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

What is cos 300°?

Answer

cos 300° =
1/2 = 0.5

Angle in radians: 300° = 5π/3. The point of the angle is in quadrant IV, where cosine is positive.

cos 300° = cos(360° − 60°) = cos 60° = 1/2

P(cos 300°, sin 300°) = (1/2, −√3/2)

Half of an equilateral triangle with side 1: the hypotenuse is 1 and the leg opposite 30° is 1/2.

cos 60° = 1/2

xyOP

P(cos 300°, sin 300°) ≈ (0.5, −0.8660)

Highlighted: the projection on the x-axis — cosine, x = 0.5.

All four functions of 300°
FunctionExact valueDecimal
sin 300°−√3/2≈ −0.8660
cos 300°1/20.5
tan 300°−√3≈ −1.7321
cot 300°−√3/3≈ −0.5774

Reference angle: cos 60° = 1/2

See Also

Recalculate with different values ↑

Cosine of nearby angles

Anglecos
270°0
285°(√6 − √2)/4
288°(√5 − 1)/4
300°1/2
306°√(10 − 2√5)/4
315°√2/2
324°(√5 + 1)/4

FAQ

What is cos 300°?

cos 300° = 1/2 = 0.5

How to remember sin 30°, sin 45° and sin 60°?

Write them as √1/2, √2/2, √3/2: sin 30° = 1/2, sin 45° = √2/2, sin 60° = √3/2. Cosines are the same numbers in reverse order: cos 30° = √3/2, cos 45° = √2/2, cos 60° = 1/2; tan = sin / cos and cot = cos / sin. Here: cos 300° = 1/2 = 0.5.

Why does a calculator show −0.0221 for cos 300?

The calculator is in radian mode (RAD): it takes cos 300 as the cosine of 300 radians, cos 300 rad ≈ −0.0221. Switch it to degrees (DEG): cos 300° = 1/2 = 0.5. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also