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# expm1

From cppreference.com
< c‎ | numeric‎ | math

Defined in header `<math.h>` |  |
float expm1f( float arg ); |  | (since C99)
double expm1( double arg ); |  | (since C99)
long double expm1l( long double arg ); |  | (since C99)

Computes the e (Euler's number, `2.7182818`) raised to the given power `arg`, minus 1. This function is more accurate than the expression exp(arg)-1 if `arg` is close to zero.

### [edit] Parameters

arg | - | floating point value

### [edit] Return value

earg
-1

If the result is too large for the underlying type, range error occurs and HUGE_VAL is returned.

### [edit] See also

exp | returns e raised to the given power (ex) (function) [edit]
exp2 (C99) | returns 2 raised to the given power (2x) (function) [edit]
C++ documentation for expm1

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