Cos 130 Degrees

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

What is cos 130°?

Answer

cos 130° ≈
−0.6428

Angle in radians: 130° = 13π/18. The point of the angle is in quadrant II, where cosine is negative.

≈ — rounded to 4 decimal places. cos 130° can't be written with square roots: 130° is not a multiple of 3°.

cos 130° = cos(180° − 50°) = −cos 50° ≈ −0.6428

P(cos 130°, sin 130°) ≈ (−0.6428, 0.7660)

xyOP

P(cos 130°, sin 130°) ≈ (−0.6428, 0.7660)

Highlighted: the projection on the x-axis — cosine, x ≈ −0.6428.

All four functions of 130°
FunctionExact valueDecimal
sin 130°—≈ 0.7660
cos 130°—≈ −0.6428
tan 130°—≈ −1.1918
cot 130°—≈ −0.8391

Reference angle: cos 50° ≈ 0.6428

See Also

FAQ

What is cos 130°?

cos 130° ≈ −0.6428

Why does cos 130° 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°. 130° is not, so no such exact form exists; the value is used as a decimal: cos 130° ≈ −0.6428.

Why does a calculator show −0.3673 for cos 130?

The calculator is in radian mode (RAD): it takes cos 130 as the cosine of 130 radians, cos 130 rad ≈ −0.3673. Switch it to degrees (DEG): cos 130° ≈ −0.6428. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.