Cos 70 Degrees

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

What is cos 70°?

Answer

cos 70° ≈
0.3420

Angle in radians: 70° = 7π/18. The point of the angle is in quadrant I, where cosine is positive.

≈ — rounded to 4 decimal places. cos 70° can't be written with square roots: 70° is not a multiple of 3°.

P(cos 70°, sin 70°) ≈ (0.3420, 0.9397)

xyOP

P(cos 70°, sin 70°) ≈ (0.3420, 0.9397)

Highlighted: the projection on the x-axis — cosine, x ≈ 0.3420.

All four functions of 70°
FunctionExact valueDecimal
sin 70°—≈ 0.9397
cos 70°—≈ 0.3420
tan 70°—≈ 2.7475
cot 70°—≈ 0.3640

See Also

FAQ

What is cos 70°?

cos 70° ≈ 0.3420

Why does cos 70° 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°. 70° is not, so no such exact form exists; the value is used as a decimal: cos 70° ≈ 0.3420.

Why does a calculator show 0.6333 for cos 70?

The calculator is in radian mode (RAD): it takes cos 70 as the cosine of 70 radians, cos 70 rad ≈ 0.6333. Switch it to degrees (DEG): cos 70° ≈ 0.3420. In radians the value is never undefined: π is irrational, so a whole number of radians never lands exactly on an axis.