//Example 26.4
d_i=(-100+1.5)*10^-2;//Image distance (m)
d_o=(25-1.5)*10^-2;//Object distance (m)
P=1/d_o+1/d_i;//Power (D)
printf('Power of spectacle lens required = %0.2f D',P)
//Openstax - College Physics
//Download for free at http://cnx.org/content/col11406/latest