Math Is Fun Forum

the problem gives the function of x as: f(x)= 1/x

Im confused as to the steps that lead to the answer: -1/a^2

i know the formula for finding this is :

lim                (a+h)-(a)/h
h->0
i can get to here just fine -> ( 1/(a+h) - (1/h) ) / h

but somehow i always wind up getting -h/(a^2+ah)
what am i doing wrong?

any help is appreciated,