Find the derivative of f(x)=-(9)/(x) at x=6

Question

parthkohli · Answer

$$f(x) = \dfrac{-9}{x}$$Is that the function?

anonymous · Answer

$$f(x)= - \frac{ 9 }{ x }$$

anonymous · Answer

@ParthKohli

parthkohli · Answer

Yeah, the same thing.

Heard of the product rule or the quotient rule? Either will work here.

anonymous · Answer

Wait parthy..

parthkohli · Answer

Sure, waiting.

parthkohli · Answer

Oh yeah!

anonymous · Answer

$$\frac{d}{dx}(x^n) = n \cdot x^{n-1}$$

parthkohli · Answer

Yeah, that.

anonymous · Answer

And remember:
$$\frac{1}{x^a} = x^{-a}$$

parthkohli · Answer

$$f(x) = -9x^{-1}$$We have a winner here.

parthkohli · Answer

Grr, why did I even mention the Product Rule.

anonymous · Answer

@ParthKohli @waterineyes I'm lost

parthkohli · Answer

Have you heard of the Power Rule?$$\dfrac{d}{dx}(x^n) = n x^{n - 1}$$

anonymous · Answer

@ParthKohli no

anonymous · Answer

Net got disconnected..

Yeah, we have @ParthKohli here..

parthkohli · Answer

@Ambition That's sad... :-|

parthkohli · Answer

What all do you know about differentiation and derivatives?

anonymous · Answer

@ParthKohli nothing

anonymous · Answer

@Ambition Sorry I have to ask this question. Why didn't your teacher teach you the power rule?

parthkohli · Answer

@Ambition I'm afraid I can't help you then. Take a look at your course notes and lectures.

anonymous · Answer

@BABYShawol184 he was barely in school @ParthKohli thanks for your help

anonymous · Answer

Wow. Well good luck @ParthKohli helped a lot so you should be good :) Good Luck ^.^

anonymous · Answer

the  derivative of the reciprocal function $$f(x)=\frac{1}{x}$$ is$$f'(x)=-\frac{1}{x^2}$$ it is a very common function, best to simply memorize it