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atan

Inverse tangent in radians

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Syntax

Y = atan(X)

Description

Y = atan(X) returns the Inverse Tangent (tan-1) of the elements of X in radians. The function accepts both real and complex inputs.

  • For real values of X, atan(X) returns values in the interval [-π/2, π/2].

  • For complex values of X, atan(X) returns complex values.

example

Examples

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Open Live Script

Find the inverse tangent of a value.

atan(0.8)
ans = 
0.6747
Open Live Script

Find the inverse tangent of the elements of vector x. The atan function acts on x element-wise.

x = [0.5i 1+3i -2.2+i];
Y = atan(x)
Y = 1×3 complex

   0.0000 + 0.5493i   1.4615 + 0.3059i  -1.2019 + 0.1506i
Open Live Script

Plot the inverse tangent function over the interval -20≤x≤20.

x = -20:0.01:20; 
plot(x,atan(x))
grid on

Figure contains an axes object. The axes object contains an object of type line.

Input Arguments

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Tangent of angle, specified as a scalar, vector, matrix, multidimensional array, table, or timetable. The atan operation is element-wise when X is nonscalar.

Data Types: single | double | table | timetable
Complex Number Support: Yes

More About

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Inverse Tangent

The inverse tangent is defined as

tan−1(z)=i2log(i+zi−z).

This definition of the atan function returns angles in radians within the interval [-π/2, π/2]. To find the four-quadrant inverse tangent, where the returned angles are in the interval [-π, π], use atan2.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Version History

Introduced before R2006a

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See Also

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