What is the lim q>p of [f(p+q)-f(p)]/q?

[TitoSmooth]

I did. [f(p)+f(q)-f(p)]/q = f(q)/q

Can anyone explain what the f outside of parenthesis mean? Is it function of letter? and what's the answer.

Thanks.

 

[Decimae]

Why do you say $f(p + q) = f(p) + f(q)$. Do you know what $f$ means? If so, you haven't given that the function $f$ is linear, so you can't do that.

If you don't know what $f$ means, it means it is a function(probably, based on what you need to calculate). A function is a way to notate something done on a number, for instance take the function $g$ which we define to be $g(x) = x^2$ for all real numbers $x$. Then $g(2) = 4$, for instance. That also means that $g(p + q) = (p + q)^2 = p^2 + 2pq + q^2 \neq p^2 + q^2 = g(p) + g(q)$.

 

[TitoSmooth]

sorry.

it is basicly problem 7. pg 104 in Morris Kline Calculus.

what is Lim q→0 [f(p+q)-f(p)]/q.

what does this mean? the f(terms) are confusing me.

Im in the section where we learn X^n rule of derivatives.

 

[LCKurtz]

sorry.

it is basicly problem 7. pg 104 in Morris Kline Calculus.

what is Lim q→0 [f(p+q)-f(p)]/q.

what does this mean? the f(terms) are confusing me.

Im in the section where we learn X^n rule of derivatives.

Are you given a particular function $f$ to begin with? Or is it just some unknown function? If you think of $q=h$ and $p=x$ you have$$
\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}$$Is that familiar?

 

[TitoSmooth]

Nope not familiar and it does not say its a function or not.

 

[dirk_mec1]

Is q>p or is q ->p?

 

[TitoSmooth]

q---> as q nears p

 

[vela]

What is Lim q→0 [f(p+q)-f(p)]/q.

what does this mean? the f(terms) are confusing me.

I'm in the section where we learn X^n rule of derivatives.

What specifically is confusing you? It was explained above that f denotes a function.

 

[TitoSmooth]

What specifically is confusing you? It was explained above that f denotes a function.

Can I have a step by step explanation of the question I posted? How do I find the limit of the problem.

 

[Mark44]

Can I have a step by step explanation of the question I posted? How do I find the limit of the problem.

You're fairly new here, so might not be clear on how things work at PF. Per the rules of this forum, we don't do your work for you.

In the rules, under Homework Help Guidelines:

Under no circumstances should complete solutions be provided to a questioner, whether or not an attempt has been made.

It seems pretty obvious to me that the expressions f(p + q) and f(p) are function notation, and the limit suggests a difference quotient, a basic concept in calculus. It would actually be a difference quotient if it were like this:
$$\lim_{q \to 0}\frac{f(p + q) - f(p)}{q}$$
This isn't what you wrote, though, as you have q approaching p rather than 0.

A more serious problem is that you converted f(p + q) to f(p) + f(q), which is almost never a valid step. As you said earlier, you didn't understand what the notation f(p) meant, which tells me that you will have a very difficult time in calculus until you fill this gap in your knowledge.

 

[SammyS]

It seems pretty obvious to me that the expressions f(p + q) and f(p) are function notation, and the limit suggests a difference quotient, a basic concept in calculus. It would actually be a difference quotient if it were like this:
$$\lim_{q \to 0}\frac{f(p + q) - f(p)}{q}$$
This isn't what you wrote, though, as you have q approaching p rather than 0.

What Mark44 wrote is exactly the problem you referred to.

The book asks you,

What is $\displaystyle \lim_{q \to 0}\frac{f(p + q) - f(p)}{q}\ \ ?$

 

[Mark44]

What Mark44 wrote is exactly the problem you referred to.

The book asks you,

What is $\displaystyle \lim_{q \to 0}\frac{f(p + q) - f(p)}{q}\ \ ?$

From the thread title, the limit was as q --> p, which doesn't make much sense. I didn't notice that in post #3, the OP changed it to q --> 0.

 

[SammyS]

Yes, the limit is as q --> 0 .