Program FactorHW
c     This program uses the power series for e^x to compute variables
c     of a pre-defined set to find cosh(x) and compares them to those of
c     power series.
c     ****Nathan Hayes 4/16/08****

      real ans, ans2, x

      do x = -1.0, 1.1 , 0.1
        ans = (fexp(x) + (1./fexp(x)))/2.
        ans2 = cosh(x)
        print 20, x, ans, ans2
20    format(1x, f5.1, 2f15.5)
      enddo
      end



      function fexp(x)
      external Factor
      real sum, x, a
      a = 0
      sum = 0
      do while(abs(sum-exp(x)) .gt. 10**(-5))
         sum = sum+x**a/factor(a)
         a = a + 1
      enddo
      end
      


      function Factor(x)
      integer  i
      real Factor, x
      Factor = 1.
      i=x
      do while (i.ge.1)
         factor=factor*i
         i=i-1
         end do
      end