# economic algebraic demand+supply.

• Mar 22nd 2014, 03:54 AM
Lisa1714
economic algebraic demand+supply.
Hello I'm a university student who hasn't done any maths in the last 3 years or so. Basically im a law/commerce student and one of my core subjects for commerce is economic. I done economics in high school and was amongst the highest. However high school economic has very little maths and is more just theory. So one of the things I need to know is how to use algebra for demand and supply. I attached the questions I cant answer hopefully someone can teach me. Attachment 30484 6,8,9,10 are questions I can answer. Its no problem if noone can help but i would appreciate if someone tries. Thanks Lisa.
• Mar 22nd 2014, 06:59 AM
JeffM
Re: economic algebriac demand+supply.
Hi Lisa

I'm a bit confused, a state my wife says is normal for me. You say you can do problems 6, 8, 9, and 10, but those are the ones that involve "solving" an algebra problem. Most of the rest involve understanding the concepts and vocabulary of basic price theory, sometimes called partial equilibrium analysis. Almost all economics today is summarized in the language of mathematics, and partial equilibrium analysis is easily understood in terms of a simple graph.

The idea is this. Quantity demanded of X is considered the dependent variable of a function where the independent variable is a unit price of X. That demand function has a non-positive slope. Quantity supplied of X is considered the dependent variable of a function where again the independent variable is the unit price. That supply function has a non-negative slope. There is equilibrium when the price is such that quantity supplied and quantity demanded are equal. Graphically it is the intersection of two curves. What happens to the intersection point if one curve is shifted and the other stays the same. It involves comparing different equilibria.

We can help. Tell us the first problem that gives you trouble and what work you have done on that problem or what ideas you have so we can see where you are stuck
• Mar 23rd 2014, 01:48 AM
Lisa1714
Re: economic algebriac demand+supply.
oh sorry i meant those questions i cant answer. I am good with all the theoretical concepts and some basic maths ones like elasticity and so but when i get lost when algebra comes in. The problem is i dont know where to start in learning how to answer them. I am so backwards with maths and I don't intend on doing economic or any maths based major. I have a checklist of what I should know for the mid semester exam which is in about 4 weeks time. If anyone can help tell me where to start I have forgotten almost all algebra but i dont want to learn things that I wont need. I attached the checklist. The maths workshops my uni offers are too advanced and geared for finance, econometrics and so students. Thank you so much for your time

-Lisa
• Mar 23rd 2014, 07:20 AM
JeffM
Re: economic algebriac demand+supply.
Quote:

Originally Posted by Lisa1714
oh sorry i meant those questions i cant answer. I am good with all the theoretical concepts and some basic maths ones like elasticity and so but when i get lost when algebra comes in. The problem is i dont know where to start in learning how to answer them. I am so backwards with maths and I don't intend on doing economic or any maths based major. I have a checklist of what I should know for the mid semester exam which is in about 4 weeks time. If anyone can help tell me where to start I have forgotten almost all algebra but i dont want to learn things that I wont need. I attached the checklist. The maths workshops my uni offers are too advanced and geared for finance, econometrics and so students. Thank you so much for your time

-Lisa

Lisa

Your attachment indicates that your course requires you to memorize a few formulas and to solve linear and quadratic equations in one unknown and linear equations in two unknowns. That's it.

I have several suggestions for you. First, look up on google Khan Academy YouTube Algebra 1. It is an excellent review of the kind of math required for this course. Second, do not get agitated about calculus. They give you the formulas for the derivatives you are expected to know and do not really expect you to understand ANY calculus.

Third, let's take the problems you are having difficulty with ONE AT A TIME. For the first such problem, either show us your work up to the point where you got stuck, or if you have not done any work, tell us what ideas you have on what might work. Finding out what SPECIFICALLY you need help on means we have to see how far you can go on your own. It will do you no good on your test if we give you answers rather than methods to get answers because we shall not be with you when you take the test.
• Mar 24th 2014, 02:35 AM
Lisa1714
Re: economic algebriac demand+supply.
Thank you for the reply and for the reassurance, because i was seriously freaking out over the calculus. Ill watch those videos you suggested and then try to do the problems. Thanks again
• Mar 24th 2014, 08:43 AM
JeffM
Re: economic algebriac demand+supply.
Quote:

Originally Posted by Lisa1714
Thank you for the reply and for the reassurance, because i was seriously freaking out over the calculus. Ill watch those videos you suggested and then try to do the problems. Thanks again

Lisa

In case you come back, and now that you mentioned calculus, which I suspected might be a source of concern: the math guidelines try to introduce some calculus notation and to explain the main use of a function's derivative, but they also give you formulas. No understanding of the math is required to use a formula.

A function's first derivative equals zero at every local minimum and maximum so finding derivatives is a way to find things like where cost is minimized or profit maximized. The derivative is also used in quantifying elasticities.

HOWEVER, they imply that they will not use any functions except linear and quadratic ones, and they give you the formula the derivatives of such functions. So it is just a matter of plugging in formulas.

Personally I do not like that method of teaching, and it appears that whoever wrote up the math review tried to sneak a little math into what is basically a cheat sheet.