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acos.hpp
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1 #ifndef STAN__AGRAD__FWD__FUNCTIONS__ACOS_HPP
2 #define STAN__AGRAD__FWD__FUNCTIONS__ACOS_HPP
3 
4 #include <stan/agrad/fwd/fvar.hpp>
5 #include <stan/meta/traits.hpp>
6 #include <stan/math/functions/square.hpp>
7 #include <math.h>
8 
9 namespace stan {
10 
11  namespace agrad {
12 
13  template <typename T>
14  inline
15  fvar<T>
16  acos(const fvar<T>& x) {
17  using ::acos;
18  using ::sqrt;
19  using stan::math::square;
20 
21  return fvar<T>(acos(x.val_), x.d_ / -sqrt(1 - square(x.val_)));
22  }
23  }
24 }
25 #endif
stan::math::square
T square(const T x)
Return the square of the specified argument.
Definition: square.hpp:22
stan::agrad::acos
var acos(const var &a)
Return the principal value of the arc cosine of a variable, in radians (cmath).
Definition: acos.hpp:60
stan::agrad::acos
fvar< T > acos(const fvar< T > &x)
Definition: acos.hpp:16
stan::agrad::square
fvar< T > square(const fvar< T > &x)
Definition: square.hpp:15
stan::agrad::sqrt
fvar< T > sqrt(const fvar< T > &x)
Definition: sqrt.hpp:15
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