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Calculates the cube root of a number

#include <math.h>
double cbrt ( double x  );
float cbrtf ( float x  );
long double cbrtl ( long double x  );

The cbrt( ) functions return the cube root of their argument x.


#define KM_PER_AU (149597870.691) // An astronomical unit is the mean
                                  // distance between Earth and Sun:
                                  // about 150 million km.
#define DY_PER_YR (365.24)

double dist_au, dist_km, period_dy, period_yr;

printf( "How long is a solar year on your planet (in Earth days)?\n" );
scanf( "%lf", &period_dy );

period_yr = period_dy / DY_PER_YR;
dist_au = cbrt( period_yr * period_yr );    // by Kepler's Third Law
dist_km = dist_au * KM_PER_AU;

printf( "Then your planet must be about %.0lf km from the Sun.\n", sma_km );

See Also

sqrt( ), hypot( ), pow( )

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