text: /************************************************************************
   * libc/math/lib_acosf.c
   *
   * This file is a part of NuttX:
   *
   *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
   *   Ported by: Darcy Gong
   *
   * It derives from the Rhombs OS math library by Nick Johnson which has
   * a compatibile, MIT-style license:
   *
   * Copyright (C) 2009, 2010 Nick Johnson <nickbjohnson4224 at gmail.com>
   * 
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   * 
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   *
   ************************************************************************/
  
  /************************************************************************
   * Included Files
   ************************************************************************/
  
  #include <math.h>
  
  /************************************************************************
   * Public Functions
   ************************************************************************/
  
  float acosf(float x)
  {
    return (M_PI_2 - asinf(x));
  }
  