## anonymous one year ago Find the derivative of f(x) = 6x + 2 at x = 1.

1. anonymous

2. triciaal

is the question complete?

3. anonymous

Derivative is simply the slope at the point at which it is asked isn't it? Your question seems a little arbitrary

4. triciaal

the derivative is a constant 6

5. triciaal

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6. mathstudent55

$$\dfrac{d}{dx} x^n = nx^{n - 1}$$ $$\dfrac{d}{dx} k = 0$$ $$\dfrac{d}{dx} k \cdot u(x) = k \cdot \dfrac{d}{dx}u(x)$$

7. anonymous

I'm sorry for the late reply. I was away from my laptop. Anyway, should I use this formula?

8. anonymous

With the formula, I got 6, is that correct?

9. anonymous

To find the derivative at x = 1 I would substitute 1 for x; however there is no x to substitute remaining. Therefore, the derivative of f(x) = 6x + 2 at x = 1 is 6.

10. mathstudent55

Let me give you an analogy to answer your question. If you are in elementary school just learning how to divide numbers using long division, then, if you use a calculator to do a division, you are cheating. If on the other hand, you are taking college physics, and you need to divide two numbers, then most likely you are expected to use a calculator. The way you take the derivative depends on the context. If you are just learning about derivatives, and all you have till now is the definition of derivative with the limit that you just posted, then take the derivative that way. If you already learned other easier ways of taking the derivative, then do that instead. It's very hard for helpers in OS to know exactly at what level of learning you are unless you tell us. That's why our advice may be general at times.

11. anonymous

Don't worry, next time I would indicate the knowledge that I only know. I just thought that helpers in OS would explain the steps in solving the problem and not only put formulas. Thank you for your time. @mathstudent55

12. zepdrix

poo, hah! 6 is correct :) all good?

13. mathstudent55

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