mathematical formula.........

[jerem488]

I have a mathematical formula of which I would like to find the result of 2 variables

I must find the result => 52

My 2 varaibles are "x" and "y"

the formula is ==>>

$result = 0.95(2(((x+y)-2*y)-0.2)/2+((PI*y"power"3*0.7(2230-355.94ln(y))/32((x/y)+0.07/(x/y)-0.075))/0.016666)/360)-y)

I don't know how to proceed ! !

THANK YOU in advance

[weaponx]

What the hell is this formula? Do you know how difficult and time consuming it is to have to get a specific result when there is more than one variable?

[raj2734]

What the hell is this formula? Do you know how difficult and time consuming it is to have to get a specific result when there is more than one variable?

I think you may be overthinking what he wants but maybe not. From your post it looks like you think he wants to solve for x and y. Which is quite difficult and to do effectivly requires differential equations which I have forgotten how to do over the years. However I think he has x and y and wants to solve for the result. Is this correct Jerem488?

If it is "power" is simply using '^'

ln does not appear to be directly supported however you do have the function "log. " Unless my math skills are failing me now, which they very well may be, you can get the same result of ln(x)= (Log(x)/Log(e)) where e= 2.71828182845905.

PI of course is 3.1459265

Good Luck

[monoceres]

If it is "power" is simply using '^'

ln does not appear to be directly supported however you do have the function "log. "

In AutoIt, Log() is in fact Ln().

[jerem488]

I think you may be overthinking what he wants but maybe not. From your post it looks like you think he wants to solve for x and y. Which is quite difficult and to do effectivly requires differential equations which I have forgotten how to do over the years. However I think he has x and y and wants to solve for the result. Is this correct Jerem488?

If it is "power" is simply using '^'

ln does not appear to be directly supported however you do have the function "log. " Unless my math skills are failing me now, which they very well may be, you can get the same result of ln(x)= (Log(x)/Log(e)) where e= 2.71828182845905.

PI of course is 3.1459265

Good Luck

yes sorry, "power" is "^" !

If you couldnt ans to this question, I will make differently. But in all the the cases i must resolve thi problem.

thank you

Edited October 14, 2008 by jerem488

[raj2734]

In AutoIt, Log() is in fact Ln().

Ah I guess if I had read "Return Value Success: Returns the parameter's natural logrithm." I would have seen that for myself. I just assumed it was base10 for some reason. Its been awhile since I've had to deal with mathematics in any form.

Jerem488 you have all the necessary information. I was wrong about the natural log as monceres pointed out but you can simply use log(x) instead its the same as ln(x). I gave you power and PI is just a number, you can make it a variable if you really want to.

[andybiochem]

Did you really mean you wanted the result to be => 52 .....i.e greater than or equal to, or did you just mean equal to??

Also, the parentheses aren't balanced, and you need to put * where you want to multiply.

This gives some integer solutions....

$pi = 3.141592

Do

$x = Random(0,100,1)
$y = Random(0,100,1)

$result = 0.95 * (2 * ((($x+$y)-2*$y)-0.2)/2+(($pi*$y^3*0.7 * (2230-355.94 * log($y))/32 * (($x/$y)+0.07/($x/$y)-0.075))/0.016666)/360)-$y

Until $result >= 52


MsgBox(0,"","x = " & $x & "   y = " & $y)

Change >= to = if you meant 'equal to 52'.......and leave it running for a few days whilst you read up on Turing's Halting Problem.

[jerem488]

Did you really mean you wanted the result to be => 52 .....i.e greater than or equal to, or did you just mean equal to??

Also, the parentheses aren't balanced, and you need to put * where you want to multiply.

This gives some integer solutions....

$pi = 3.141592

Do

$x = Random(0,100,1)
$y = Random(0,100,1)

$result = 0.95 * (2 * ((($x+$y)-2*$y)-0.2)/2+(($pi*$y^3*0.7 * (2230-355.94 * log($y))/32 * (($x/$y)+0.07/($x/$y)-0.075))/0.016666)/360)-$y

Until $result >= 52


MsgBox(0,"","x = " & $x & "   y = " & $y)

Change >= to = if you meant 'equal to 52'.......and leave it running for a few days whilst you read up on Turing's Halting Problem.

NOOOOOOOOOOO ! ! ! ! STOP !

It's very exelent ! !!

VERY THANKS

I would not have thought that it was so easy.

Very thanks andybiochem.

[jerem488]

So excuse me but can we to be more just ??

Because the random isn't the best choice for this...

And I want the result is imperatively 52

I have test to put this :

$pi = 3.141592

Do

$x = Random(0,100,1)
$y = Random(0,100,1)

$result = 0.95 * (2 * ((($x+$y)-2*$y)-0.2)/2+(($pi*$y^3*0.7 * (2230-355.94 * log($y))/32 * (($x/$y)+0.07/($x/$y)-0.075))/0.016666)/360)-$y

Until $result = 52


MsgBox(0,"","x = " & $x & "   y = " & $y)

But it's very long.......

Can we use the command "For" rather random ??

Edited October 14, 2008 by jerem488

[Chapi]

So excuse me but can we to be more just ??

Because the random isn't the best choice for this...

And I want the result is imperatively 52

I have test to put this :

$pi = 3.141592

Do

$x = Random(0,100,1)
$y = Random(0,100,1)

$result = 0.95 * (2 * ((($x+$y)-2*$y)-0.2)/2+(($pi*$y^3*0.7 * (2230-355.94 * log($y))/32 * (($x/$y)+0.07/($x/$y)-0.075))/0.016666)/360)-$y

Until $result = 52


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[YellowLab]

Without a constraint on how x and y are related, there isn't "one" solution to the problem. For every x chosen, there is one or more y values that will satisfy the conditions. Do you want to solve y = f(x)? Do you want to plot the result? Is there another constraint regarding how x and y are related?

Bob

[andybiochem]

try this:

$found = 0

$pi = 3.141592

For $x = 1 to 100 Step 0.1
    For $y = 1 to 100 Step 0.1
        $result = 0.95 * (2 * ((($x+$y)-2*$y)-0.2)/2+(($pi*$y^3*0.7 * (2230-355.94 * log($y))/32 * (($x/$y)+0.07/($x/$y)-0.075))/0.016666)/360)-$y
        If $result = 52 Then 
            $found = 1
            ExitLoop 2
        EndIf
    Next
Next

If $found = 1 Then
    MsgBox(0,"","x = " & $x & "   y = " & $y)
Else
    MsgBox(0,"","No solution found")
EndIf

change the x and y limits, and also try changing the step values.

I'm not sure there's a soltuion to this.

[jerem488]

try this:

$found = 0

$pi = 3.141592

For $x = 1 to 100 Step 0.1
    For $y = 1 to 100 Step 0.1
        $result = 0.95 * (2 * ((($x+$y)-2*$y)-0.2)/2+(($pi*$y^3*0.7 * (2230-355.94 * log($y))/32 * (($x/$y)+0.07/($x/$y)-0.075))/0.016666)/360)-$y
        If $result = 52 Then 
            $found = 1
            ExitLoop 2
        EndIf
    Next
Next

If $found = 1 Then
    MsgBox(0,"","x = " & $x & "   y = " & $y)
Else
    MsgBox(0,"","No solution found")
EndIf

change the x and y limits, and also try changing the step values.

I'm not sure there's a soltuion to this.

Result ==> no solution found

And if I don't specify the step ???

I have test without and the result is the same ==>> no solution found

Edited October 14, 2008 by jerem488

[YellowLab]

The reason no solution is found is there are not any rational numbers that solve the conditions. Once you pick an x value, you can solve for the y value numerically. Here are some "solved" values from excel:

x     y
1     1.483060636
2     1.050886771
3     0.838243534
4     0.711812033
5     0.625853159
10  0.411515292
15  0.313334766

This is done by picking an x value, i.e. "1" and a guess for y

Now your function is only one variable f(y) as x is set at your initial pick. A numerical method can be used to solve for y.

I tried Newton's method but it didn't converge well. I don't know what solver algorithm Excel uses.

Bob

[trancexx]

To point up what YellowLab is saying.

To see what is the "problem" here try to resolve this much simpler equation:

x^2 + y^2 = 1

That is done like this:

x^2 + y^2 = 1 | *(1/y^2) ; y <> 0 -(multiplying with 1/y^2)

(x/y)^2 + 1 = 1/y^2 | x/y = t -making substitution

t^2 + 1 = 1/y^2 that is to say that y^2 = 1/(1+t^2)

therefore x^2 = t^2/(1+t^2)

So, the solution(s):

x^2 = t^2/(1+t^2)

y^2 = 1/(1+t^2)

for every t ∈ Z ; ( Z = {, -2, -1, 0, 1, 2, })

How many solutions are there?

edit:

actually, for for every t ∈ R ; R - the set of all real numbers

Edited October 15, 2008 by trancexx

[YellowLab]

It does help if I used the right methodology. This gives results slighlty different than excel:

#include <Array.au3>
Global Const $pi = 3.14159265358979

$step=0.001
$convergence = 0.000001
$result = 52
$func="0.95 * (2 * ((($x+$y)-2*$y)-0.2)/2+(($pi*$y^3*0.7 * (2230-355.94 * _log($y,10))/32 * (($x/$y)+0.07/($x/$y)-0.075))/0.016666)/360)-$y-$result"

Dim $arResult[101][2]
For $x = 1 to 100
    $y = $x/2
    Do 
        $f_0 = _Fofx($x,$y,$result)
        $ytemp=$y-$step/2
        $temp1 = _Fofx($x,$ytemp,$result)
        $ytemp=$y+$step/2
        $temp2 = _Fofx($x,$ytemp,$result)
        $fprime_0 = ($temp2 - $temp1) / $step
        $newy=$y-($f_0/$fprime_0)
        $diff=abs($newy-$y)
        $y=$newy
    Until $diff <= $convergence
    $arResult[$x][0]=$x
    $arResult[$x][1]=$y
Next
_ArrayDisplay($arResult)

Func _log($x, $base)
    Return Log($x) / Log($base)
EndFunc

Func _Fofx($x,$y, $result)
    Return Execute($func)
EndFunc

Good luck!

Bob

EDIT:

Updated the code to show Log base 10 rather than natural log. Don't know which is necessary. Also, refined the algorithm slightly in the calculation of the derivative at $x and added a little more precision to pi. Now the output matches Excel's solver values.

Edited October 15, 2008 by YellowLab