inverse trig functions

Is there a short hand way in C to return the inverse sine and cosine values for an input variable? i have found how to use the EEFROM library to display averaged values for the time derivative of data collected by sensors but im thinking if i need to do something similar to get a taylor series approximation to the inverse trig i would feel more comfortable with more than 512 slots. does the ether-mega have more than 512? ive lost the papers it came with.

void setup( void )
{
}

void loop( void )
{
  asin( 0.0 );
  acos( 0.0 );
}
void setup ()
  {
  Serial.begin (115200);
  Serial.println (asin (1), 6);
  }  // end of setup

void loop () { }

Output:

  1.570796

Thanks very much appreciated guys!!

i have found how to use the EEFROM library to display averaged values for the time derivative of data collected by sensors

Storing values in EEPROM could cause problems if you do it too often because there is a limit as to how many times you can reliably write to an EEPROM location. How frequently are the values stored and over what period ?