Arctan of −2

Arcsin, Arccos, Arctan, Arccot
Function
x

What is arctan(−2)?

Answer

arctan(−2) ≈
−63.4349° ≈ −1.1071 rad

Range: arctan x is an angle strictly between −90° and 90°, so the answer is unique.

≈ — the value is not a table one; rounded to 4 decimal places.

arctan(−2) is the angle α in (−90°, 90°) with tan α = −2.

arctan(−2) = −arctan(2) ≈ −63.4349°

tan(−63.4349°) ≈ −2.0000

xyOPT

α = arctan(−2) ≈ −63.4349°

P ≈ (0.4472, −0.8944)

T(1, −2) is where line OP meets the line x = 1; highlighted: tan α = −2.

All four inverse functions of −2
FunctionDegreesRadians
arcsin(−2)does not exist—
arccos(−2)does not exist—
arctan(−2)≈ −63.4349°≈ −1.1071
arccot(−2)≈ 153.4349°≈ 2.6779

See Also

Recalculate with different values ↑

Arctangent of nearby values

xarctan x
−3≈ −71.5651°
−2≈ −63.4349°
−√3−60° = −π/3
−4/3≈ −53.1301°
−1−45° = −π/4
−4/5≈ −38.6598°
−√3/3−30° = −π/6

FAQ

What is arctan(−2)?

arctan(−2) ≈ −63.4349° ≈ −1.1071 rad

Why is arctan(−2) ≈ −63.4349°?

arctan is an odd function: arctan(−x) = −arctan x. So arctan(−2) = −arctan(2) ≈ −63.4349°, and this angle lies in the range (−90°, 90°).

Why does a calculator show −1.1071 for arctan(−2)?

The calculator is in radian mode (RAD) and gives the angle in radians: arctan(−2) ≈ −1.1071 rad. In degrees (DEG) it is ≈ −63.4349°.

See Also