||'''Book''' ||Modern Physics ||
 ||'''Author''' ||Kennith Krane ||
 ||'''Edition''' ||Second||



/* code_begins */

{{{
var('r a')
a=0.529e-10
p=r**4*e**(-r/a)/(24*a**5)
print solve([diff(p,r)==0],r)[0]/a, "times a0"
}}}
/* code_ends */

 * '''Solution by''':
  * Sabareesh Nikhil C,student,IIT Bombay