expm1()

Published Jul 20, 2021Updated Dec 21, 2022
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The expm1() function returns e raised to the power of the argument minus 1. For small magnitudes of x expm1(x) may be more accurate than exp(x)-1.

The number e, also known as Euler’s number, is a mathematical constant approximately equal to 2.71828 and the base of the natural logarithm.

The cmath library must be added to the top of the file with #include <cmath>.

Syntax

Returns eⁿ - 1:

std::expm1(n)

Example

Use expm1() to return the value of e³-1:

double result;
result = std::expm1(3);

Codebyte Example

Use expm1() to return the value of e-1 (e¹-1):

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