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From the original equation:
[1] x-1801+sqrt[(y-1860)*(x-1801)] = 2*sqrt(x-1801) - 1
[2] sqrt[(y-1860)*(x-1801)] = -(x-1801)+ 2*sqrt(x-1801) - 1
[3] sqrt[(y-1860)*(x-1801)] = -[sqrt(x-1801) - 1]^2
Also from the original equation:
x-1801 > 0
x > 1801
From the equation [3] above:
The right side is always negative.
And for the sqrt on left side to exist, the right side should be 0.
[4] [sqrt(x-1801) - 1] = 0
[5] sqrt(x-1801) = 1
[5] (x-1801) = 1
[6] x = 1801 + 1
[7] x = 1802
Also the left side of [3] should be zero.
[8] sqrt[(y-1860)*(x-1801)] = 0
[9] (y-1860)*(x-1801) = 0
By replacing x = 1802
[10] (y-1860)* 1 = 0
[11] (y-1860) = 0
[12] y = 1860
Therefore, there is one solution only:
x = 1802
y = 1860
One solution is:
x=1802
y=1860
What do you say? I say it has everything to do with understanding what is going on in the problem.
By the way, I am not talking about simple problems...
Indeed, this is the first step in designing every part of a new application.
If y=x+2 we can write y=f(x)=x+2
If y=h+2 we can write y=f(h)=h+2
If z=w+2 we can write z=f(w)=w+2
...
In brief, the notation f(a) means that we have a function (its name could be any symbol) in which the 'independent' variable is 'a'.
For example:
If y=3*x+2*a +1 and we read y=f(a), it means that 'x' here is not the independent variable of 'y', it is just added aa a parameter. In this case, we plot 'y' versus 'a', for each value of the parameter 'x' of interest. But saying y=f(x), 'x' is the independent variable and 'a' is the parameter in 'y'.
The main, if not crucial, role of the human scientific brain is to find out the formula, the function or the equation which can emulate/reflect, as possible, a real problem that needs to be solved.
Therefore, the purpose of the various math's exercises is to gain, also as possible, the logical reasoning on how to get the required/needed results from analyzing a formula/function of interest or solving a well-defined equation(s). Fortunately, there are also many ready-made tools to assist someone in doing this to save time (after he learns how to use them).
KerimF wrote:[img]https://i.imgur.com/a/IbFoc46.jpeg[/img]
https://i.imgur.com/a/IbFoc46.jpeg
This time it didn't work on my side.That's the link to the webpage containing the image, not to the image on it. It shouldn't have the .jpeg extension.
Here's an image of that webpage. It's just a small version of it, done by using the letter 't' (for small) size modifier before the '.jpeg' extension:
https://i.imgur.com/XGtFi7kt.jpg
The link to the image on that webpage is this:
[img]https://i.imgur.com/xx9dW9G.jpeg[/img]
And here's the image:
https://i.imgur.com/xx9dW9G.jpegl
Thank you.
The calculus way is based on the knowledge of the derivatives of functions.
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).
Thank you, Bob.
Your steps are much better than mine.
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.
It seems you did it.
But on my side, I just see the file name of a hidden image which is 'IbFoc46.jpeg'.
[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]
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
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.
What confuses me is how one gives a result as 'a range' and as 'a domain'!
"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.
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
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?
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.
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
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.
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
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.
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.