Question

I really need help, I don't understand how to find marginal cost and revenue...

Answer 1

marginal dhould bring derivatives to mind

Answer 2

*should

Answer 3

if cost = C(x), marginal cost is C'(x)

if revenue = R(x), marginal revenue is R'(x)

Answer 4

I don't exactly know what to do though. Is there a formula other than that.

Answer 5

derivative rules ... unless you want to run thru first principles: given a function f(x), the marginal stuff can be calculated as\[\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}\]

Answer 6

So the function f(x) is what though? Like I f I have quantity, price, total revenue, and total cost. But I do not have marginal revenue, marginal cost, and profit? How do I fill everything out in the equation.

Answer 7

f(x) is just a generic function notation for whatever you revenue function is (or cost function, or whatever function you are trying to marginalize)

Answer 8

do you have a specific function that you would like to have marginalized?

Answer 9

I have to make a graph. But for an example, I was giving quantity of 4, price was 38, total revenue was 152 and then total cost was 114.

Answer 10

total cost should amount to: variable cost (times units sold) + fixed costs but the information you have provided is prolly taken out of some broader context.

Answer 11

revenue - cost = gross income before taxes :/

Answer 12

So can I still find what I am looking for with what I gave you?

Answer 13

not really; there is no way i see with that scant information to develop any rule/expression to play with.

Answer 14

if i we to ask you to find the slope of a line at the point (4,6); the solution is rather unobtainable simply because at a single point (and no expression for getting to that point) there is no way to develop the tolls necessary to calcualte it

Answer 15

lets take the functions: y = x^2, y=x^3 ; the point (1,1) satisfies both equation; but the "marginal" results differ:

y' = 2x, at x=1 is 2
y' = 3x^2 at x=1 is 3

Answer 16

*to develop the tools ... not tolls :)

Answer 17

I think I am getting it now.

Answer 18

but what is the exponent 2 for?

Answer 19

that was just some easy random functions to demonstrate that if all you are given is a point, there is no way to define the "marginal" aspects related to that point without a defininte expression

Answer 20

different expressions yeild different results

Answer 21

quantity-
price total revenue marginal revenue total cost marginal cost profit
0 84 0 70
1 82 82 136
2 80 160 188
3 78 234 214
4 76 304 228
5 74 370 258
6 72 432 360
7 70 490 470
8 68 544 592

Answer 22

that is what was given me

Answer 23

the one all the way to the left is quantity, it gave me no profit

Answer 24

the 70 column is total cost tho right?

Answer 25

revenue = price, times quantity; you have a linear setup such that:

price = 2q + 84

revenue = q(2q+84), or just 2q^2+84q

marginal revenue would be based off of that setup

Answer 26

price is 84-2q ... that is

Answer 27

revenue = q(84-2q), or just 84q - 2q^2

you agree?

Answer 28

Okayy, Yes I agree.

Answer 29

then the marginal value for each q can be obtained from the expression: 84-4q if we were to run it thru that f(x+h)-f(x) limit definition i presented above

Answer 30

http://www.wolframalpha.com/input/?i=table+84-4n%2C+n%3D0+to+10

Answer 31

the cost function is not wanting to be linear for us :/

Answer 32

So what does that mean?

Answer 33

that just means that trying to determine a suitable cost function is more difficult

Answer 34

Great, just what I need. Lol I am so grateful you are helping me this much. You are a life saver!

Answer 35

profit is just revenue minus cost ... so that column is pretty basic

Answer 36

So profit doesn't have to do with marginal al all?

Answer 37

marginal profit would :) but if its just labeled as profit ... then no; take the revenue and subtract the cost to get profit

Answer 38

ima try to do an excel run for the cost .. make life simpler maybe

Answer 39

this is what the cost data gives us as a graph, notice that it doesnt make a nice straight line

Answer 40

well, the library decided to "upgrade" to excel 2013 ... which of course has to not have anything in the right places to do anything that you could do with excel 2010 with ....