Sin 98 Degrees

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

What is sin 98°?

Answer

sin 98° ≈
0.9903

Angle in radians: 98° = 49π/90. The point of the angle is in quadrant II, where sine is positive.

≈ — rounded to 4 decimal places. sin 98° can't be written with square roots: 98° is not a multiple of 3°.

sin 98° = sin(180° − 82°) = sin 82° ≈ 0.9903

P(cos 98°, sin 98°) ≈ (−0.1392, 0.9903)

xyOP

P(cos 98°, sin 98°) ≈ (−0.1392, 0.9903)

Highlighted: the projection on the y-axis — sine, y ≈ 0.9903.

All four functions of 98°
FunctionExact valueDecimal
sin 98°—≈ 0.9903
cos 98°—≈ −0.1392
tan 98°—≈ −7.1154
cot 98°—≈ −0.1405

Reference angle: sin 82° ≈ 0.9903

See Also

Recalculate with different values ↑

Sine of nearby angles

Anglesin
89°≈ 0.9998
90°1
97°≈ 0.9925
98°≈ 0.9903
100°≈ 0.9848
101°≈ 0.9816
105°(√6 + √2)/4

FAQ

What is sin 98°?

sin 98° ≈ 0.9903

Why does sin 98° 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°. 98° is not, so no such exact form exists; the value is used as a decimal: sin 98° ≈ 0.9903.

Why does a calculator show −0.5734 for sin 98?

The calculator is in radian mode (RAD): it takes sin 98 as the sine of 98 radians, sin 98 rad ≈ −0.5734. Switch it to degrees (DEG): sin 98° ≈ 0.9903. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also