Sin 300 Degrees

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

What is sin 300°?

Answer

sin 300° =
−√3/2 ≈ −0.8660

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

≈ — rounded to 4 decimal places.

sin 300° = sin(360° − 60°) = −sin 60° = −√3/2

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.

sin 60° = √(1 − 1/4) = √3/2

xyOP

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

Highlighted: the projection on the y-axis — sine, y ≈ −0.8660.

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: sin 60° = √3/2

See Also

FAQ

What is sin 300°?

sin 300° = −√3/2 ≈ −0.8660

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: sin 300° = −√3/2 ≈ −0.8660.

Why does a calculator show −0.9998 for sin 300?

The calculator is in radian mode (RAD): it takes sin 300 as the sine of 300 radians, sin 300 rad ≈ −0.9998. Switch it to degrees (DEG): sin 300° = −√3/2 ≈ −0.8660. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.