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#151 Re: Help Me ! » Find Domain & Range » 2024-03-18 00:59:14
Just a note.
Here, it is clear that:
Domain is for x (supposed being an independent variable) and Range is for y (supposed being a dependent variable, function of x).
#152 Re: Help Me ! » Sequences; finding the formula that gives us the nth term » 2024-03-18 00:46:13
Thank you, Bob.
Your steps are much better than mine.
#153 Re: Help Me ! » Find Domain & Range » 2024-03-18 00:27:25
Here is the image:
http://i.imgur.com/aflDtIp.gif
I don't know why it won't display as the syntax looks correct to me.
Bob
It works here too. Perhaps your image was uploaded in a different way.
#154 Re: Help Me ! » Find Domain & Range » 2024-03-17 22:26:03
It seems you did it.
But on my side, I just see the file name of a hidden image which is 'IbFoc46.jpeg'.
#155 Re: Help Me ! » Use Graph to Find Domain and Range » 2024-03-17 22:19:13
[img]https://i.imgur.com/a/IbFoc46.jpeg[/img]
This time it didn't work on my side.
But the following one is ok.
[img]https://i.imgur.com/7NtStGDl.jpeg[/img]
#156 Re: Help Me ! » Sequences; finding the formula that gives us the nth term » 2024-03-17 22:10:33
KerimF wrote:How did you come up with the formula?
I did it by following primitive steps since I forgot, at age 75, the advanced ones.
f(n) = f(n-1)*2+1
f(n-1) = f(n-2)*2+1
f(n) = (f(n-2)*2+1)*2+1
f(n-2) = f(n-3)*2+1
f(n) = ((f(n-3)*2+1)*2+1)*2+1
f(n-3) = f(n-4)*2+1
f(n) = (((f(n-4)*2+1)*2+1)*2+1)*2+1
f(n-4) = f(n-5)*2+1
f(n) = ((((f(n-5)*2+1)*2+1)*2+1)*2+1)*2+1
f(n) = ((((f(n-5)*2+1)*2+1)*2+1)*2+1)*2+1
f(n) = (((f(n-5)*2+1)*2+1)*2+1)*2*2+2+1
f(n) = (((f(n-5)*2+1)*2+1)*2*2*2+2*2+2+1
f(n) = (((f(n-5)*2+1)*2*2*2*2+2*2*2+2*2+2+1
f(n) = f(n-5)*2*2*2*2*2+2*2*2*2+2*2*2+2*2+2+1
f(n) = f(n-a)*2^a… +2^(a-1)+2^(a-2)+2^(a-3)+2^(a-4)+1
Um=k*r^(m-1)
In the following series
… +2^(a-1)+2^(a-2)+2^(a-3)+2^(a-4)+1
we have
k=1
m=a
f(n) = f(n-a)*2^a+2^(a)-1
f(n) = 2^a*[f(n-a)+1]-1
Let us assume:
n-a=1
n=a+1
f(a+1) = 2^a*[f(1)+1]-1
But
f(1)= 2
Therefore
f(a+1) = 2^a*3-1
Again, let us assume:
a+1=n
a=n-1
f(n) = 2^(n-1)*3-1
f(n) = 3*2^(n-1)-1 #157 Re: Help Me ! » Find Domain of A » 2024-03-17 22:02:17
KerimF wrote:What confuses me is how one gives a result as 'a range' and as 'a domain'!
I don't understand your confusion.
Find the domain is not the same as find the range.
I type all questions as stated in the textbooks.
Sorry if I gave you the impressing that I am arguing with you or else. Please note that I believe whatever you say.
I just knew things in math that are somehow different from what I see here sometimes. That is all.
So, when in doubt, I believe that Bob, for example, can help clarifying the math definitions of interest, as they are followed on his side and yours.
On my side, I have no reason not to accept anything you say. After all, at work, I don't follow any definition. I just solve math problems and get numerical/practical results.
#158 Re: Help Me ! » Find Domain of A » 2024-03-17 12:22:50
What confuses me is how one gives a result as 'a range' and as 'a domain'!
#159 Re: Help Me ! » Sequences; finding the formula that gives us the nth term » 2024-03-17 12:00:16
#160 Re: Help Me ! » Find Domain of A » 2024-03-17 02:51:47
"Given A(x) = 4x•sqrt{1 - x^2}, find the 'domain' of A."
A(x) is supposed to be a dependent variable, so I expected to read... find the 'range' of A.
#161 Re: Help Me ! » Find Ground Speed of Plane » 2024-03-17 02:33:00
Try the graph here:
https://www.mathsisfun.com/data/function-grapher.php
You'll need to drag around and zoom out to find the curve. It never crosses the x axis so you won't find a solution that way. With calculus you can find the minimum. Without it you'll have to read off from the graph.
Bob
Hi Bob,
This 'grapher' page doesn't seem to work!
Kerim
Edited:
It didn't when I entered y as: 100+x/10+36000/x
It did when enter it as: x/10+36000/x+100
#162 Re: Help Me ! » Use Graph to Find Domain and Range » 2024-03-17 02:00:08
How come it's not working for me?
I suggest, till you will succeed doing it on your side, that you may like to include the URL of your image of interest with a posted question and the first member who will read your post will attach it to a subsequent post for you (as I did here).
What do you think?
#163 Re: Help Me ! » Use Graph to Find Domain and Range » 2024-03-17 01:33:03
FelizNYC wrote:I don't have time to repeat the process now. Going to work. Remind me on Wednesday and Thursday (my days off) to go over whatever it is that I did.
I'll try to remember.
Btw, my link in post #12 has an error (the closing square bracket is missing).
I've fixed it, and this is the correct link:
[img]https://i.imgur.com/7NtStGD.jpeg[/img]Just copy that link and paste it into a post to display the image.
The reason the image doesn't display in my post is that I've enclosed the link in 'Code' tags, which deactivates the img tags (see the section headed 'Code' in BBCode, about 2/3rds down the page).
Thank you for clarifying this point.
I will try it here too before our friend Feliz will do.
I also appended the lettelr 'l' before ".jpeg" since the image is somehow big.
#164 Re: Help Me ! » Find Domain of A » 2024-03-17 00:51:32
Hi Bob,
It seems that that 'range and 'domain' could be applied both on the variable or the function.
I thought, so I may be wrong, that 'domain' is for the variable only and 'range' is for the function only.
Please clarify this point.
Thank you.
Kerim
#165 Re: Help Me ! » Analyze h(x) » 2024-03-17 00:45:01
Given h(x) = (-32x^2)/(130)^2, do A to C.
D. Find all interceptsTo find the x-intercept(s), I must let h(x) = 0.
Yes?To find the y-,intercept(s), I must let x = 0.
Yes?
Both correct.
#166 Re: Help Me ! » Analyze h(x) » 2024-03-17 00:43:21
Given h(x) = (-32x^2)/(130)^2, do A to C.
B. Find domain of h algebraically
I expected to read instead:
B. Find domain of x algebraically
#167 Re: Help Me ! » Analyze h(x) » 2024-03-17 00:40:06
A ok.
Bob
Ok?!
I see him just replacing h(x) with a zero:
0 = (-32x^2)/(130)^2
I guess he needs to go on a bit further to deduce the value of x.
#168 Re: Help Me ! » Determine Function N » 2024-03-13 04:42:46
The best, fastest and simplest tactic to gain 'huge' amount of money from the ordinary people/multitudes of a country is ... (fill the gap) 
Added:
Hint: It doesn't work with me in the way I live.
#169 Re: Help Me ! » Cross-sectional Area » 2024-03-12 20:59:04
Did they also tell you what is better for you to do instead of what you are doing?
Every human, he likes or not, has to find out how to fill the time which is given to him from his birth to his death.
So, almost every human tries his best to prove, to himself and others, that he knows how to fill his time better than how others do.
This is a universal fact that will exist always in human's life.
On my side, since after year 2011 (when the world launched its terror war in my region) I have just worked to get my daily bread only (yes, nothing else). I even have no more suitable dresses to go out. Fortunately, I didn't need to go to a doctor in this long period of time. Meanwhile, I gave all profits which I gain from designing and producing new electronic products (needed by the local consumers) to my few assistants (and their families). Why I live this way? I do it because this how I feel fine in filling my time. Naturally, most people around me, if not all, find really hard to understand how a professional designer in electronics accepts to live this way (and staying in his room, day and night, with his old laptop and old devices/stuff related to electronics).
I mean, in general, one cannot really please himself and others as well, at the same time. Only a clever deceiver can manage to do it
#170 Re: Help Me ! » Difference Quotient of f » 2024-03-10 01:54:07
Could it be simplified?
#171 Re: Help Me ! » Find the Function g » 2024-03-10 01:43:04
His wrong line is:
[(1/x)(x + 1)]/(x^2 - 1)
The right one is:
(1/x) / [(x + 1)/(x^2 - x)]
He was just in a hurry
So he skipped:
(f/g)(x) * g(x) = f(x)
g(x) = f(x) / (f/g)(x)
#172 Re: Help Me ! » Find the Value of B » 2024-03-10 01:31:01
Let me see it in reverse.
f(x) = 3x^2 - Bx + 4 with x=-1 and B=5
f(-1) = 3*((-1)^2) - (5)*(-1) + 4
f(-1) = 3 + 5 + 4 = 12
Your B=5 is right for sure.
#173 Re: Help Me ! » Find the Function g » 2024-03-10 01:19:19
Given f(x) = 1/x and (f/g)(x) = (x + 1)/(x^2 - x), find the function g.
Let me see.
(f/g)(x) = f(x)/g(x).
Let me see:
(f/g)(x) = f(x) / g(x)
(f/g)(x) * g(x) = f(x)
g(x) = f(x) / (f/g)(x)
g(x) = (1/x) / [(x + 1)/(x^2 - x)]
g(x) = (1/x) * (x^2 - x) / [(x + 1)
...
#174 Re: Help Me ! » Find Domain of Functions...2 » 2024-03-09 22:23:25
I'd not met the backwards square bracket notation. But, if it means the same as a round bracket then that's fine.
This crops up all the time in maths; there's no absolute authority to appeal to. I use Wolfram Alpha but there's no rule book for anything.
Bob
So, nothing prevents this forum to have its own rule book for math so that its members can understand each other properly when they write certain math's notations.
Naturally, those in charge of this forum may like to start doing such a rule book (then updating it with time) and let it be available to all.
#175 Re: Help Me ! » Find Domain of Functions...2 » 2024-03-09 21:17:00
I agree with you both.
For instance, at my French school (about 58 years ago) we used to write:
[1, 4] which means that the domain is from 1 to 4 with 1 and 4 included.
]1, 4[ which means that the domain is from1 to 4 but 1 and 4 are not included.
]1, ∞] which means that the domain is from 1 to ∞ but 1 ia not included. Infinity was included always since any big number that one may imagine of is included
I learnt from you that the above examples are now written as:
[1, 4]
(1, 4)
(1, ∞)