.

[bootymac]

.

 

[tatteredpotato]

Do you know how to take the derivative?

 

[bootymac]

.

 

[tatteredpotato]

Ohhhhh boy....... well a derivative is the equation for the slope of the tangent line.

To make this quick you need a quotient rule for derivation and that is:

Derivative of top times bottom - derivative of bottom times top all over bottom squared

Derivative of top is a product rule and that is

First times derivative of second + second times derivative of first.

to take the derivative of a variable, you multiply by the exponent, then subtract one from it and it becomes your new exponent. Derivative of constants is 0

 

[bootymac]

.

 

[TimMyMac]

It looks like you are doing basic dirivitives. limit as X goes to 7 from what the questions says. Go into your text book and find the rate of change equation. It should look something like (f(x+h) - F(x)) / h. (where H = 0) You plug the equation that you have into that, reduce it till you can get rid of the X/0 and then plug in the 0 for h, reduce some more, and then plug in the 7 for x. That should do it.

 

[TimMyMac]

BTW - There are some power and quotent rules that you can use to solve it really quickly but it doesn't look like you've gotten there yet. You've gotta do it the hardway first.

 

[Savij]

Tell us what yesterday's lecture was about so we can tell you what today's lecture was on.

 

[bootymac]

Originally posted by: TimMyMac
It looks like you are doing basic dirivitives. limit as X goes to 7 from what the questions says. Go into your text book and find the rate of change equation. It should look something like (f(x+h) - F(x)) / h. (where H = 0) You plug the equation that you have into that, reduce it till you can get rid of the X/0 and then plug in the 0 for h, reduce some more, and then plug in the 7 for x. That should do it.

Ah, I tried doing this earlier but I had problems plugging the function into the equation. I don't know why but I'm confused as hell :roll:

And by 7 do you mean 9?

 

[tatteredpotato]

This is something you should probably just get help on next time ur in class. This is very important in calculus and it's pretty hard to learn on the message board. We could give u an answer, but your better off learning how to do that.

 

[bootymac]

Originally posted by: BlameCanada
This is something you should probably just get help on next time ur in class. This is very important in calculus and it's pretty hard to learn on the message board. We could give u an answer, but your better off learning how to do that.

The problem is that this online assignment is due before class tomorrow morning, so I'm pretty much SOL. Unless you're willing to give me answers and I try to work backwards to learn how to do this. :heart:

 

[TimMyMac]

ya, what ever the value that it gave you was. If your getting confused on that your going to have to talk to your professor, You need someone to explain the Algebra of it to you and that's hard to do over the internet. The idea is that your using the equation to find M (slope) like you would for a linear equation. But instead of using Y as your top values, your subbing in F(x) values instead (it's the same thing just a step back). The H is a modification to it that makes it easier to use. Do you remember Rise/Run? It's the same thing, your just finding it for a equation that has a ever changing slope. The equation that you get after all is said and done is the dirived equation that the Y values of it represent the slope of the original equation at that same X value. Talk to your professor and try some easier equations. That one's a toughy to start out with.

 

[OREOSpeedwagon]

you should have gone to your lecture, derivatives are kind of important to calculus

 

[bootymac]

Originally posted by: TimMyMac
ya, what ever the value that it gave you was. If your getting confused on that your going to have to talk to your professor, You need someone to explain the Algebra of it to you and that's hard to do over the internet. The idea is that your using the equation to find M (slope) like you would for a linear equation. But instead of using Y as your top values, your subbing in F(x) values instead (it's the same thing just a step back). The H is a modification to it that makes it easier to use. Do you remember Rise/Run? It's the same thing, your just finding it for a equation that has a ever changing slope. The equation that you get after all is said and done is the dirived equation that the Y values of it represent the slope of the original equation at that same X value. Talk to your professor and try some easier equations. That one's a toughy to start out with.

I'm understand the process of doing it, but the actual "doing" part is where I get stuck. I get the examples in the text because they are a lot simplier, but there's nothing close to this question with the exponent, product, and quotient rule all in one.

 

[bootymac]

What does the top line of the tangent slope equation look like with the substitution?

 

[dopcombo]

btw, just out of interest, are you in university or in high school?

i've heard people tell me that freshmen in engineering school in the US don't know calculus but i refused to believe those stories. just wondering, that's all, so pls don't take offence OP.

 

[bootymac]

.

 

[Kirby]

you're just now getting to derivatives? how long have u been in school? we're doing antiderivatives now. i'm in first year cal, btw.

 

[tatteredpotato]

This ones moderately difficult, im getting 74.96 for the slope at 9. Anyone else try it, i may have messed up that one.

 

[bonkers325]

lim........ f(x+h) - f(x)
............ ___________
............
h->0..... h

that is the basic derivative function. it'll be easier if you consolidate your equation by taking it out of fraction form. f(9) = -260 something, f'(9) = -45 something.

 

[bootymac]

.

 

[tatteredpotato]

FYI i also didn't do it the long way.

 

[BrownTown]

Where I went to high school we did derivitives my junior year. I still don't know what the heck you do in class time to not be on calculus in high school. I mean you take pre-algebara 7th grade, algebra 8th grade, Algebra 2 9th grade, geometry 10th grade, Calc I 11th grade, Calc II as a senior. What did you do in your 6 years of hich school not have done this by the time you were in college?

Also, you don't need any facncy quotient rules, this is just the derivitive of a polynomial, should take 10 seconds to do.

 

[bootymac]

.

 

[bonkers325]

Originally posted by: bootymac

Originally posted by: nkgreen
you're just now getting to derivatives? how long have u been in school? we're doing antiderivatives now. i'm in first year cal, btw.

Here's the deal. The prof for our calc is some Chinese guy that doesn't know how to speak good english, and he can't teach for the life of him. I think our class is way behind everyone else, and we're still delaying assignments because our prof can't teach!

I'm definitely getting my money's worth here :roll:

like you're getting your money's worth by not showing up to class :roll:

grow up, you're in college. if your prof cant teach, you will have to try harder to pick up the slack - because it'll happen again. and again. and again.