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exp(3)									exp(3)

       exp,  expm1, log, log2, log10, log1p, pow - Exponential, logarithm, and
       power functions

       #include <math.h>

       double exp(
	       double x ); float expf(
	       float x ); long double expl(
	       long double x ); double expm1(
	       double x ); float expm1f(
	       float x ); long double expm1l(
	       long double x ); double log(
	       double x ); float logf(
	       float x ); long double logl(
	       long double x ); double log2(
	       double x ); float log2f(
	       float x ); long double log2l(
	       long double x ); double log10(
	       double x ); float log10f(
	       float x ); long double log10l(
	       long double x ); double log1p(
	       double y ); float log1pf(
	       float y ); long double log1pl(
	       long double y ); double pow(
	       double x,
	       double y ); float powf(
	       float x,
	       float y ); long double powl(
	       long double x,
	       long double y );

       Math Library (libm)

       Interfaces documented on this reference page conform to industry	 stan‐
       dards as follows:

       exp():  XPG4

       expm1():	 XPG4-UNIX

       log():  XPG4

       log10():	 XPG4

       log1p():	 XPG4-UNIX

       pow():  XPG4

       Refer  to  the  standards(5)  reference page for more information about
       industry standards and associated tags.

       The exp(), expf(), and expl() functions compute the value of the	 expo‐
       nential	function,  defined  as e**x, where e is the constant used as a
       base for natural logarithms.

       The expm1(), expm1f(), and expm1l() functions compute exp(x) - 1	 accu‐
       rately, even for tiny x.

       The  log(),  logf(),  and logl() functions compute the natural (base e)
       logarithm of x.

       The log2(), log2f(), and log2l() functions compute the base 2 logarithm
       of x.

       The  log10(), log10f(), and log10l() functions compute the common (base
       10) logarithm of x.

       The log1p(), log1pf(), and log1pl() functions  compute  log(1+y)	 accu‐
       rately, even for tiny y.

       The  pow(),  powf(), and powl() functions raise a floating-point base x
       to a floating-point exponent y. The value of pow(x,y)  is  computed  as
       e**(yln(x))  for	 positive  x. If x is 0 or negative, see your language
       reference manual.

       Passing a NaN input value to pow() produces a  NaN  result  for	y  not
       equal to 0. For pow(NaN,0), see your language reference manual.

       The  following  table describes function behavior in response to excep‐
       tional arguments:

       Function			       Exceptional Argument	   Routine  Behav‐
       exp(), expf(), expl()	       x > ln(max_float)	   Overflow
       exp(), expf(), expl()	       x < ln(min_float)	   Underflow
       expm1(), expm1f(), expm1l ()    x > ln(max_float)	   Overflow
       expm1(), expm1f(), expm1l ()    x < ln(min_float)	   Underflow
       log(), logf(), logl()	       x < 0			   Invalid   argu‐
       log(), logf(), logl()	       x = 0			   Overflow
       log2(), log2f(), log2l ()       x < 0			   Invalid   argu‐
       log2(), logf2(), log2l ()       x = 0			   Overflow
       log10(), log10f(), log10l ()    x < 0			   Invalid   argu‐
       log10(), log10f(), log10l ()    x = 0			   Overflow
       log1p(), log1pf(), log1pl ()    1+y < 0			   Invalid   argu‐
       log1p(), log1pf(), log1pl ()    1+y = 0			   Overflow
       pow(), powf(), powl()	       y ln(x) > ln(max_float)	   Overflow
       pow(), powf(), powl()	       y ln(x) < ln(min_float)	   Underflow

       The following table lists boundary values used by these functions:

       Value Name      Data Type   Hexadecimal Value   Decimal Value
       ln(max_float)   S_FLOAT	   42B17218	       88.7228391
		       T_FLOAT	   40862E42FEFA39EF    709.7827128933840
       ln(min_float)   S_FLOAT	   C2CE8ED0	       -103.2789
		       T_FLOAT	   C0874385446D71C3    -744.4400719213813


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