definitions

[Ryan$]

Hi guys, something is really confusing me and it's really struggling me alot maybe I understand the definition wrongly .

the teacher said , there's k constant, and x is variable .. what's the different between those? he didn't put value on "k" constant, he said a is any specific value and it's constant ..

I see that two those "k,x" are variables .. how is a constant and we didn't put on it a specific value? if a a constant then I can take 5,6,7,8,9,8,1 .. so it's variable and not constant .. any help please to differentiate between constant and variable?!

 

[HallsofIvy]

A letter represents a "constant" or a "variable" for a specific calculation. If we are told that "y= kx" is a function, where k is a constant and x is a variable, then any specific value of k gives us a function. If, say, k= 2, y= 2x is the function with variable x. If k= 5, y= 5x is another function with variable x. In each case, k is a constant, x is the variable. We can change the value of k, getting a different function but for each function, k is a constant.

 

[Dr.Peterson]

What we call a constant is unchanging "for now", while we solve a particular problem, while a variable changes within the problem.

Suppose you were doing an experiment with gases, where the volume is affected by the mass, temperature, and pressure. If we hold the temperature and mass constant while varying the pressure, we can discover how volume is related to pressure under those conditions. Then we might do another experiment with a different constant temperature, again varying the pressure. So pressure and volume are variables within each experiment, while temperature is a constant within each experiment (also called a parameter). Meanwhile, mass is also a constant, but we are never changing that.

It's all a matter of context.

 

[Ryan$]

Thanks alot guys!

 

[Ryan$]

What we call a constant is unchanging "for now", while we solve a particular problem, while a variable changes within the problem.

Suppose you were doing an experiment with gases, where the volume is affected by the mass, temperature, and pressure. If we hold the temperature and mass constant while varying the pressure, we can discover how volume is related to pressure under those conditions. Then we might do another experiment with a different constant temperature, again varying the pressure. So pressure and volume are variables within each experiment, while temperature is a constant within each experiment (also called a parameter). Meanwhile, mass is also a constant, but we are never changing that.

It's all a matter of context.

I cant understand that parameter is a constant within the problem itself, but can be changed out of the problem, I mean the parameter can be anything but once given then it's a constant within the problem yeah?!

 

[Ryan$]

what's confusing me is like that, the teacher write on the board like this: 1+2+3.....+k.....+n
he said that n is variable , and k is constant .. and what's weird for me that the teacher said "lets assume arrived to k specific" but it's not given in the question itself that k is constant ... so we can also like what you said Dr.Peterson to assume a constant k while solving although didn't give as that k is constant?!(the k isn't mention in the question itself .. it's like a help for us)


To sum up, can I assume while solving a question any constant k/a/b/c and solve over it through analyzing the problem?

 

[HallsofIvy]

I strongly suspect you are misquoting your teacher. In any case, you should be asking your teacher what he or she means.

 

[mmm4444bot]

once given then [k is] a constant within the problem yeah?!

Not always. It depends on the specific exercise.

… To sum up, can I assume while solving a question any constant k/a/b/c …

No, you may not do that. (What you may assume depends on the specific exercise.) For example, constant k may have infinite values within the same exercise. Other times, it does not.

Send me a specific exercise (by private conversation), and if it makes sense then I will edited it into your post and reopen this discussion. Until then, this thread remains closed.

\(\;\)