Defined in header <cmath> | ||
---|---|---|
(1) | ||
float atan ( float arg ); | ||
float atanf( float arg ); | (since C++11) | |
double atan ( double arg ); | (2) | |
(3) | ||
long double atan ( long double arg ); | ||
long double atanl( long double arg ); | (since C++11) | |
double atan ( IntegralType arg ); | (4) | (since C++11) |
arg
double
).arg | - | value of a floating-point or Integral type |
arg
(arctan(arg)) in the range [- π/2 , +π/2] radians, is returned. If a range error occurs due to underflow, the correct result (after rounding) is returned.
Errors are reported as specified in math_errhandling
.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
POSIX specifies that in case of underflow, arg
is returned unmodified, and if that is not supported, an implementation-defined value no greater than DBL_MIN
, FLT_MIN
, and LDBL_MIN
is returned.
#include <iostream> #include <cmath> int main() { std::cout << "atan(1) = " << atan(1) << " 4*atan(1) = " << 4*atan(1) << '\n'; // special values std::cout << "atan(Inf) = " << atan(INFINITY) << " 2*atan(Inf) = " << 2*atan(INFINITY) << '\n' << "atan(-0.0) = " << atan(-0.0) << '\n' << "atan(+0.0) = " << atan(0) << '\n'; }
Output:
atan(1) = 0.785398 4*atan(1) = 3.14159 atan(Inf) = 1.5708 2*atan(Inf) = 3.14159 atan(-0.0) = -0 atan(+0.0) = 0
(C++11)(C++11) | computes arc sine (\({\small\arcsin{x} }\)arcsin(x)) (function) |
(C++11)(C++11) | computes arc cosine (\({\small\arccos{x} }\)arccos(x)) (function) |
(C++11)(C++11) | arc tangent, using signs to determine quadrants (function) |
(C++11)(C++11) | computes tangent (\({\small\tan{x} }\)tan(x)) (function) |
(C++11) | computes arc tangent of a complex number (\({\small\arctan{z} }\)arctan(z)) (function template) |
applies the function std::atan to each element of valarray (function template) |
|
C documentation for atan |
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