Use Newton's method to find the 100th root of 100.

so I got f(x)=x^100-100

used x=1 as my starting point

x2=1-(1^100-100)/(100*1^99)

=1-(-99/100)

=1.99

then I did it a couple more times and ended up with 1.97 which is not right. What did I do wrong?

eta: is their a tutorial or something for the notation on these forums?