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acos

Inverse cosine in radians

Syntax

Description

example

y = acos(x) returns the Inverse Cosine (cos-1) of the elements of x. The acos function operates element-wise on arrays. For real elements of x in the interval [-1,1], acos(x) returns real values in the interval [0,pi]. For real values of x outside the interval [-1,1] and for complex values of x, acos(x) returns complex values. All angles are in radians.

Examples

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acos(0.3)
ans =

    1.2661

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 =

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

Plot the inverse cosine function over the domain $-1 \le x \le 1$.

x = -1:.05:1;
plot(x,acos(x))
grid on

Input Arguments

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Numeric input, specified as a number, vector, matrix, or multidimensional array.

Data Types: single | double
Complex Number Support: Yes

More About

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Inverse Cosine

The inverse cosine is defined as

cos1(z)=ilog[z+i(1z2)1/2].

Tall Array Support

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

See Also

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Introduced before R2006a

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