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Inverse secant in radians



Y = asec(X) returns the Inverse Secant (sec-1) of the elements of X in radians. The function accepts both real and complex inputs.

  • For real values of X in the interval [-∞, -1] and [1, ∞], asec(X) returns values in the interval [0, π].

  • For real values of X in the interval (-1, 1) and for complex values of X, asec(X) returns complex values.


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Find the inverse secant of a value.

ans = 1.9360

Find the inverse secant of the elements of vector x. The asec function acts on x element-wise.

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

   1.5708 + 1.4436i   1.4749 + 0.2970i   1.9503 + 0.1833i

Plot the inverse secant function over the intervals -5x-1 and 1x5.

x1 = -5:0.01:-1;
x2 = 1:0.01:5;
hold on
grid on

Input Arguments

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Secant of angle, specified as a scalar, vector, matrix, multidimensional array, table, or timetable. The asec 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 Secant

The inverse secant is defined as


Extended Capabilities

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

Version History

Introduced before R2006a

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See Also

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