Question 1066026
f(x+h)=1/(x+h)
f(x+h)-f(x) all divided by h
(1/(x+h)-1/(x))= 1/(x+h)(x){x-(x+h)}
The numerator becomes -h
The denominator, (x+h)(x)=(x^2+xh)h
Divide by h top and bottom
have -1/x(x+h)
Let h approach 0, we have -1/(x^2), which is the derivative.