A math doubt in differentiation

[hyebyekadal]

Ey Everybody..
It's been two years.. since my last post, anyway...I had a doubt..

find f'(x) from first principles:

f(x)= 2x - (1/x)

I know the ans is 2 +1/x from differention rules but what are the steps to reach that through first principles?

Thanks in advance!

Cheers

[Vin]

Long method.
http://www.intmath.com/differentiation/3-derivative-first-principles.php