Could it be impossible to find derivative by basic definition?

[Stramonium]

(I am sorry, totally forgot about solving quadratic equations, close the topic please)

Homework Statement

Finding derivative of the equation like F(x) = 5x / (1+x^2) by definition (ƒ(a+h) - f (a))/h is easy (point 2;2), but I got really stuck in finding a way to solve it by basic definition ( f(y) - f(a) )/( x - a ) :(

It seems to me there are much more such equations. Is there any way to do it?

 

[adjacent]

Isn't that the same thing?
As far as I know, the basic definition of derivative is:

 

[Stramonium]

The same, I just had difficulties with canceling equation derived from y - y1 / x - x1, because I totally forgot about solving quadratic equations:( It seemed strange to me on that moment that I could solve the (f(h) - f(a)) / a, but not another form:) Close the topic please.

 

[dirk_mec1]

Topics are not closed without a good reason.