Find the derivative of f(x) = -12x2 + 9x at x = 6.
-112.5
-135
-90
-108
@ganeshie8 @hero @dan815 @perl @pooja195 @nincompoop @CGGURUMANJUNATH @zepedrix @usukidoll

- anonymous

- schrodinger

See more answers at brainly.com

At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your **free** account and access **expert** answers to this

and **thousands** of other questions

- nincompoop

use power rule

- anonymous

how do i do that? can u show me step by step? @nincompoop

- nincompoop

you can get the general derivative first and then apply at x=6 or you can apply it from the beginning

Looking for something else?

Not the answer you are looking for? Search for more explanations.

## More answers

- UsukiDoll

\[f(x) = -12x^2+9x \]

- nincompoop

alright, guy
what have you learned so far?

- nincompoop

have you learned derivative by limit definition yet?

- anonymous

no or maybe i did but i dont remember. can one of u show me step by step @UsukiDoll @nincompoop

- nincompoop

okay do you know what a derivative is first?

- anonymous

no @nincompoop

- nincompoop

ahhhhh

- nincompoop

do you know what a slope is?

- anonymous

once i have f(x)=-12x^2+9(x) what would i do?

- nincompoop

I can give you the general formula for power-rule, but it won't help you much in the long run if you have no clue what derivatives are.

- nincompoop

so do you know what is slope?

- nincompoop

I am asking a series of questions to see where is the proper place to begin.

- anonymous

no i dont @nincompoop

- Astrophysics

\[\frac{ d }{ dx } x^n = nx^{n-1}\] power rule

- nincompoop

man...

- nincompoop

laughing out loud

- UsukiDoll

wow nin... don't be rude -_-

- nincompoop

I'd use \(a \) instead of the coefficient n

- nincompoop

whatever floats floats

- anonymous

@UsukiDoll can u please help me

- nincompoop

alright, I think we've got a problem here
I am dumbfounded why you're doing derivative when you do not know what slopes are.

- nincompoop

in any case, we can go ahead and start with slope in general

- nincompoop

begin by our day-to-day language, slope pertains to the steepness of something
think of a slide or a hill or anything that goes down or up, it will have a slope

- nincompoop

now we can try to infuse a some math into the language

- Astrophysics

Well I don't think you have to go that far nin, I'm sure OP knows what slope is and just needs to remember |dw:1436327588479:dw| one image will do wonders

- nincompoop

I was just about to draw

- anonymous

okay i already know this?

- nincompoop

are you asking us or telling us?

- anonymous

telling u

- nincompoop

alright great!
now we can move on to derivatives! laughing out loud

- Astrophysics

But for your question, you find the derivative then plug in the value of x they've given you

- UsukiDoll

sorry I'm with another user right now.

- nincompoop

basically derivative pertains the slope at a particular instant

- nincompoop

|dw:1436327777742:dw|

- nincompoop

a good example of the instant that I am referring to is where one of the lines intersects at one point with the circle

- Astrophysics

Jessica were you taught definition\[f'(x) = \lim_{h \rightarrow 0} \frac{ f(x+h)-f(x) }{ h }\] of derivative, I think that's what you have to use

- nincompoop

now before we proceed, we must be able to identify and know about continuous functions

- nincompoop

think of this portion as an algebra recap
will you be able to tell us if the equation you're given is continuous or not?

- nincompoop

if you're unsure, now is the time to learn them
http://tutorial.math.lamar.edu/Classes/CalcI/CalcI.aspx

- nincompoop

review on tangents with pretty awesome illustration
http://tutorial.math.lamar.edu/Classes/CalcI/Tangents_Rates.aspx

- nincompoop

let us know when you've digested the concept of tangents and derivatives
because the next part will be testing your algebra skills with derivatives using limit-definition.

Looking for something else?

Not the answer you are looking for? Search for more explanations.