It might be better to consider the alternate definition:
Then you would have to compute
(Handling the remaining limit depends on how you define .)
Hi my question is :
Show that is differentiable on
I began by the definition that A function is differentiable at c if and only if
I started by however i am now unsure on how to cancel the bit.
I am not sure on how to show this.
... it has been extablished that f(x) is differentiable in x=a if there exist a real constant k such that...
Now if You remember the 'fundamental limit'...
... You from (2) derive that is...
... so that (1) is verified...