expm1

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Common mathematical functions
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remainder (C99)
remquo (C99)
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fmax (C99)
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nan
nanf
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(C99)
(C99)
(C99)
Exponential functions
exp
exp2 (C99)
expm1 (C99)
log
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log1p (C99)
log2 (C99)
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hypot (C99)
pow
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(C99)
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(C99)
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Macro constants
 
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

returns e raised to the given power (ex)
(function)
(C99)
returns 2 raised to the given power (2x)
(function)