||'''Book'''|| Calculus of One Variable ||
 ||'''Author'''|| Keith E. Hirst ||
 ||'''Edition'''||  ||

/* code_begins */

{{{
var('a,t')
x=a*cos(t)
y=a*sin(t)
y=(a*a-x^2)^0.5
z=diff(y,t)/diff(x,t)
show(integrate(2*pi*y*(1+z*z)^0.5,x,0,pi))
}}}

/* code_ends */

 * '''Solution by''': 
   * Chandrahas,student,iit madras