//Chapter-3,Example3_3_1,pg 3-6

NA=0.5                                                 //Numerical aperture

n1=1.54                                                //refractive index of core

n2=sqrt(n1^2-NA^2)                                     //Numerical aperture is 'NA^2 = n1^2 - n2^2'

printf("\nThe refractive index of cladding is  n2 = %.3f\n",n2)