program ch1301 implicit none real :: a, b, c, term, a2, root1, root2 ! a b and c are the coefficients of the terms ! a*x**2+b*x+c ! find the roots of the quadratic, root1 and ! root2 print *, ' give the coefficients a, b and c' read *, a, b, c term = b*b - 4.*a*c a2 = a*2. ! if term < 0, roots are complex ! if term = 0, roots are equal ! if term > 0, roots are real and different if (term<0.0) then print *, ' roots are complex' else if (term>0.0) then term = sqrt(term) root1 = (-b+term)/a2 root2 = (-b-term)/a2 print *, ' roots are ', root1, ' and ', root2 else root1 = -b/a2 print *, ' roots are equal, at ', root1 end if end program ch1301