Tan 98 Degrees

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

What is tan 98°?

Answer

tan 98° ≈
−7.1154

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

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

tan 98° = tan(180° − 82°) = −tan 82° ≈ −7.1154

tan 98° = sin 98° / cos 98° ≈ −7.1154

xyOP

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

T(1, tan 98°) ≈ (1, −7.1154) — where line OP meets the line x = 1, on the extension of the ray beyond O (dashed); T is beyond the drawing, the arrow points to it.

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: tan 82° ≈ 7.1154

See Also

Recalculate with different values ↑

Tangent of nearby angles

Angletan
89°≈ 57.2900
90°undefined
97°≈ −8.1443
98°≈ −7.1154
100°≈ −5.6713
101°≈ −5.1446
105°−2 − √3

FAQ

What is tan 98°?

tan 98° ≈ −7.1154

Why does tan 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: tan 98° ≈ −7.1154.

Why does a calculator show 0.6999 for tan 98?

The calculator is in radian mode (RAD): it takes tan 98 as the tangent of 98 radians, tan 98 rad ≈ 0.6999. Switch it to degrees (DEG): tan 98° ≈ −7.1154. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.

See Also