Find the derivative of the function using the definition of derivative.
the square root of 8-x

Question

Find the derivative of the function using the definition of derivative.
the square root of 8-x

dumbcow · Answer

oh the dreaded limit definition of derivatives

dumbcow · Answer

haha can i just teach you the shortcut lol

anonymous · Answer

yes

dumbcow · Answer

no that wont help you on a test

anonymous · Answer

I know that you pull down the number that is above the exponent so the x would disappear and become 1 but would the 8 also disappear?

dumbcow · Answer

so you have
$$\lim_{h \rightarrow 0} \frac{f(x+h) - f(x)}{h} = \lim_{h \rightarrow 0} \frac{\sqrt{8-(x+h)} - \sqrt{8-x}}{h}$$

dumbcow · Answer

ahh yes the 8 would disappear .... derivative of constant is 0

anonymous · Answer

so it would just be the square root of 1?

dumbcow · Answer

no because the whole thing is inside of sqare root, its a bit more complicated

anonymous · Answer

Now im confused

dumbcow · Answer

anyway are you talking about limit definition here?

dumbcow · Answer

or where are you in your calculus course? this way i know the correct approach to help you

anonymous · Answer

I am on chapter 2.8

dumbcow · Answer

whats the chapter heading ...

anonymous · Answer

Nevermind i figured it out. Thank you

dumbcow · Answer

alrighty then