Sin 89 Degrees

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

What is sin 89°?

Answer

sin 89° ≈
0.9998

Angle in radians: 89° = 89π/180. The point of the angle is in quadrant I, where sine is positive.

≈ — rounded to 4 decimal places. sin 89° can't be written with square roots: 89° is not a multiple of 3°.

P(cos 89°, sin 89°) ≈ (0.0175, 0.9998)

xyOP

P(cos 89°, sin 89°) ≈ (0.0175, 0.9998)

Highlighted: the projection on the y-axis — sine, y ≈ 0.9998.

All four functions of 89°
FunctionExact valueDecimal
sin 89°—≈ 0.9998
cos 89°—≈ 0.0175
tan 89°—≈ 57.2900
cot 89°—≈ 0.0175

See Also

Recalculate with different values ↑

Sine of nearby angles

Anglesin
86°≈ 0.9976
87°≈ 0.9986
88°≈ 0.9994
89°≈ 0.9998
90°1
97°≈ 0.9925
98°≈ 0.9903

FAQ

What is sin 89°?

sin 89° ≈ 0.9998

Why does sin 89° 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°. 89° is not, so no such exact form exists; the value is used as a decimal: sin 89° ≈ 0.9998.

Why does a calculator show 0.8601 for sin 89?

The calculator is in radian mode (RAD): it takes sin 89 as the sine of 89 radians, sin 89 rad ≈ 0.8601. Switch it to degrees (DEG): sin 89° ≈ 0.9998. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also