acos - Inverse cosine in radians - MATLAB (original) (raw)

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Inverse cosine in radians

Syntax

Description

`Y` = acos([X](#mw%5F650507f6-44ae-4502-8e48-b2feff7e90c4)) returns theInverse Cosine (cos-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, 1],acos(X) returns values in the interval [0, π].
For real values of X outside the interval [-1,1] and for complex values of X, acos(X) returns complex values.

example

Examples

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Find the inverse cosine of a value.

Find the inverse cosine of the elements of vector x. The acos function acts on x element-wise.

x = [0.5i 1+3i -2.2+i]; y = acos(x)

y = 1×3 complex

1.5708 - 0.4812i 1.2632 - 1.8642i 2.6799 - 1.5480i

Plot the inverse cosine function over the intervals -1≤x≤1.

x = -1:.01:1; plot(x,acos(x)) grid on

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

Input Arguments

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Cosine of angle, specified as a scalar, vector, matrix, multidimensional array, table, or timetable. The acos operation is element-wise whenX is nonscalar.

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

Extended Capabilities

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Theacos function fully supports tall arrays. For more information, see Tall Arrays.

Usage notes and limitations:

Generates an error during simulation and returns NaN in generated code when the input value X is real, but the output should be complex. To get the complex result, make the input value complex by passing in complex(X).

Usage notes and limitations:

Generates an error during simulation and returns NaN in generated code when the input value X is real, but the output should be complex. To get the complex result, make the input value complex by passing incomplex(X).

The acos function supports GPU array input with these usage notes and limitations:

If the output of the function running on the GPU can be complex, then you must explicitly specify its input arguments as complex. For more information, see Work with Complex Numbers on a GPU (Parallel Computing Toolbox).

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced in R2006a

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The acos function can calculate on all variables within a table or timetable without indexing to access those variables. All variables must have data types that support the calculation. For more information, see Direct Calculations on Tables and Timetables.