What is a variable? Why do we use variables to write measurement formulas?
813845
A variable is used when ANY number can fit into the equation.  For instance, for the speed equation (s = d/t, where s is speed, d is distance, and t is time),  any number we choose for d, and any number we choose for t will give us s.  A variable is just that, something that vaires.
570236
Variables are useful because they represent what we don't know. By using variables, you can create a situation in which you can solve for the unknown. \nThey can seem difficult to understand for many reasons:\n1)They represent what we don't know.\n2)They are an abstract concept.\n3)Random letters are often used to represent real things.\n4)Variables can be used in situations where nothing is related to "the real world".\n\nHope this helps!
768295
Using an equation is the lazy, mechanical way to do it. If you want to understand what's going on, factor it if possible.\n\nIf you *really* want to know what's going on, derive the quadratic formula yourself. It isn't as hard as it looks, and it can be done on one page.
846806
If you want a visual answer, a function of one variable is graphed by a line, wavy or however.  A function of two variables is graphed by a surface.  Obviously, equations with two variables take more work and effort to make anything out of them, than those with just one.
34691
Infinite number of values can be assigned. If you require a specific value, you need additional information as there are 4 variables. To be precise at least 4 different equations are required to do any further calculations.
202630
people are not here to do your homework:\n\nThis is the definition of a function:\nA variable y is a function of x if a relation between x and y produces exactly one value of y for each value of x.\n\nread it carefully, the answer to your question is quite obvious
846745
Typically you know three out of the four variables and solve for the last variable.\n\nBut sometimes they get tricky by giving you only two but one of the remaining variable is related to one or two of the given variables.
303805
I don't see how components are necessary.  \n\n"r" and "v" are just shorthand for r(t) and v(t), assuming we are looking at position (r) and velocity (v) as time varying "vectors".  And v(t) is just the time derivative of r(t) (by DEFINITION), that is, v(t) is DEFINED as r'(t).\n\nSo there isn't any actual CONTENT in expanding them into components. We are just choosing different ways to symbolize the quantities involved and there isn't anything to prove.
19284
It's a notational convenience.\n\n1) It helps avoid the problem of running out of unique symbols when working with a large, possibly infinate, set of variables.\n\n2) It provides a way to keep track of ordering in a set of variables when that ordering makes a difference.\n\n3) It makes it possible to express the values of a sequence of variables when their value depends on their position in the sequence. An example would be the Fibonacci sequence where each number in the sequence is the sum of the two previous numbers (the first two being defined as 1). It can be expressed as: \n\na(sub)1 = 1\na(sub)2 = 1\na(sub)n = a(sub)(n-1) + a(sub)(n-2)
531852
you have to use instinct, there is no clear rules that states what the expressions must look like (except if the problem insist you on giving the answer in a specific form). \n\nPerhaps one of the guidelines is make variables that have same indices grouped into one. So x + 3x becomes 4x, group them out don't leave them straying.
92874
FOR THE MOST PART EQUATIONS WITH VARIABLES LOOK LIKE THIS F(IV)=DV FOR EXAMPLE Y=2X. X IS INDEPENDENT (OR IV IN MY EQ TO THE RIGHT) AND Y IS THE DEPENDENT OR DV THE INDEPENDENT VARIABLE IS THE ONE THAT YOU CONTROL
576570
algebra...usually (well i do) set up a equation for everything, and solve for the variable. If u need help u can always get help in www.algebra.com .....
536841
First: Pay attention in class, this is stuff they teach in 7th grade. \n\nSecond: the answer is likely A because that's what the experimenter is 'controlling' but it's a very poorly worded question. The common verbage used is 'dependant' or 'independant' variables. \n\nI'm assuming that your teacher is either ignorant or very mean. Either way, my condolences.
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An Input Variable is something which you put into an experiment - so say a certain amount of chemical you put in being changed.\n\nThe Output Variable is the results you get, which will obviously change.\n\nTom Walvin\nBiology/Chemistry Student
937021
A variable is something that changes.\n\nA control is the thing in your experiment that helps show that tehre are no flaws in it.\n\nCurrently, I'm doing an experiment on the effect of color on a child's brain to follow directions. In this experiment, I give 40 children the same exact test buttt the sheet of paper's color whcih it is printed on changes.\n\nThe variable of this experiment is the different colored pieces of paper\n\nThe control would be the classroom I test it in (do the experiment in the same class each time) and the WHITE piece of paper which will show that there IS an effect.
1180441
Excel is a great tool.... I'm sorry I don't remember all the specifics but I know that there is more than one way to do it.  If you can narrow down which variables you expect to be most related that would be a great start.  If you don't have a physical (real-life) basis for that, you can try graphing all 6 variables against a column just numbered with integers from 1 to n (the number of data in each column).  Then you can plot pairs of columns against each other and find equations to fit the curves (polynomial up to 6th order, exponential, logarithmic) and use the R squared values to determine how well the equation represents the correlation of the data.  (R squared = 1 is a perfect match.)  Now when you start getting into cases where there are multiple independent variables effecting the dependent variables, it gets a little more complicated, and unfortunately I don't have Excel on this computer and I don't have my old notes or textbooks with me.  I hope this at least helps you get started.
127169
When we are trying to understand many things in the real world, like the design of machinery, or electrical systems, or the weather, we end up with many variables. Examining the system in the space of its variables is very useful; that is, one assigns a dimension to each variable, and draws pictures and analyzes the surfaces and shapes in the space of variables. If there are more than 3 variables, which there usually are, one is in a very high dimensional space.\n\nYou could not solve or analyze very many real world problems without using high dimensional analyses, such as geometry, topology, etc.