# include <math.h>

/******************************************************************************/

float f ( float t )

/******************************************************************************/
/*
  Purpose:

     F evaluates the power consumption function F(T).

  Modified:

    03 December 2006

  Author:

    John Burkardt

  Reference:

    Rubin Landau,
    A First Course in Scientific Computing,
    Princeton, 2005,
    ISBN: 0-691-12183-4
    LC: Q183.9.L36

  Parameters:

    Input, float T, the argument of the function.

    Output, float F, the value of the function.
*/
{
  float pi = 3.14159265;
  float value;

  value = ( 4.0 + t / 365.0 + 0.5 * sin ( pi * t / 91.0 ) ) * 
          ( 2.0 + exp ( - sin ( 2.0 * pi * t ) ) );

  return value;
}