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EducationRe: Nairaland Mathematics Clinic by jackpot(f): 12:03pm On Oct 22, 2013
yeah. I got it clearly. Your solution is excellent, compact and you used a totally different approach from mine. Even though your solution looks short, you lifted some things like the formula for the scale factors(h1, h2, h3) and that of the unit vectors Tu, Tv, Tphi. I bet if you included the derivations of those formulas, your solution would have clocked more pages wink

welldone, DoubleDx. Your solution is cool.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 12:06am On Oct 22, 2013
As a corollary to the above.

Assume that x depends on one variable u, viz,
x=x(u).
Differentiating both sides w.r.t. X, we have
1= Xu* Ux
therefore, Ux=1/(Xu).

This is the same as writing du/dx= 1/ (dx/du),
which is the normal relationship between the two, in single variable calculus.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 11:58pm On Oct 21, 2013
Laplacian: ...pls Maths Generals i'm so curious 2 knw d relation connectn d derivative Ux and inverse derivative Xu of a PDE...help pls!!!!!!
Given that x,y,z depends on three variables, viz,
x=x(u,v,w), y=y(u,v,w), z=z(u,v,w),
we know that the three transformed equations
u=u(x,y,z), v=v(x,y,z), w=w(x,y,z) is non-degenerate if the Jacobian of the transformation doesn't vanish.

Now, consider the equation
x=x(u,v,w).
Differentiating both sides partially w.r.t. x, we have
1=Xu Ux+ Xv Vx+ Xw Wx

so, the relationship is

Xu*Ux=1-(Xv Vx + Xw Wx)
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 11:30pm On Oct 21, 2013
Laplacian: ...@Math*Generals...any solution 2 Rhydex247's questns?....@Jackpot...ur solution is pretty...our differencies came essentially from our methods of obtainin Ux,Vx..etc...evri other thing are same...
pretty or sexy?

As for me, the solution is kinda sexy wink

i must confess, I equally learnt one or two things from the way you began your solution. It is refreshing to note that even though my first step is 100% different from yours, our first partial derivatives (and ultimately), our result essentially remains the same.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 8:00pm On Oct 21, 2013
Laplacian: ....d sum of d digits of a 2-digit number is 12, find d number if d produt of its digits must be a maximum...
The number too is 10x+y

the problem is
Maximize F(x,y)=xy
subject to x+y=12
0<=x,y<10.

You may use the Lagrange multiplier method to solve.

carefully solving it yields x=6, y=6.

Thus, the number is 66.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 7:50pm On Oct 21, 2013
Laplacian: ...d sum of d digits of a 2-digit number is nine...find d number if it must b a maximum...
The number is 10x+y

The problem is
maximize F(x,y)= 10x+y
subject to x+y=9
10>x,y > 0 integers
you may use Lagrange multiplier method.

solve and you'll get x=5 or 4, y=4 or 5. Thus, the number is 54 or 45. Sorry, I am quite busy.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:46pm On Oct 21, 2013
doubleDx: It's crazy really, I'm still on it....will post mine today or tomorrow! Sorry to y'all for what happened between Alpha & I! 1luv
*feels so happy*
Alright dear.

I dey expect your solution ooo

**rolls my mat on the floor of the thread and lies down on it, and with phone in my hand, refreshing the page** cheesy cheesy
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 7:40pm On Oct 20, 2013
i will investigate later. I sense it may have to do with the Jacobian of the transformation.

Other generals, pls help Laplacian if you are chanced
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 7:03pm On Oct 20, 2013
Laplacian: hahahahhaahhahah!!!! abeg no kill me oooo...na 4pgs d bring plenty analysis like dis?...na 12pgs...ahhahhahahahaha
ehen, na now you come wink

i don begin feel say you be James Bond. grin
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:37pm On Oct 20, 2013
Laplacian: there's one more score 2 settle
hehehe. Score kwa? No be competition oooo grin wink
you be my oga na.

Oya, feel free. Temper justice with mercy though grin
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:29pm On Oct 20, 2013
Laplacian: wit my 40leaves notebook, it barely took 4pgs
lol, I bet you that solving for Ux, Vx and Qx simultaneously from what you posted earlier will take more than a page.

Next, you will still apply your same approach to obtain Uy, Vy and Qy and it will take up to the same number of pages.

Next, you still do same for Uz, Vz and Qz. This will equally take its own page.

At least, 3 pages don go oooooo cheesy

And that is just for first partial derivatives ooo.

We neva consider how much pages the second partial derivatives (Uxx, Vxx, Qxx, Uyy, Vyy, Qyy, Uzz, Vzz, Qzz) will take. For each, you will apply quotient rule which takes, at least, 4 lines for each.

You will still obtain chain rules formula for Fxx, Fyy and Fzz.

Then, add and come simplify.(at this point, you will basically do the same thing I did, same fixed step. My own addition and simplification is 3 pages.) wink

All that in 4 pages! Bro, come on! Small salt dey am cheesy grin
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:09pm On Oct 20, 2013
Laplacian: pls can u give a description?...my mobil phone cant read dat
eeya, your phone doesnt have PDF reader? You can still view it via a PC.

Description?
I obtained Ux, Uxx, Vx, Vxx, Qx, Qxx, Uy, Uyy, Vy, Vyy, Qy, Qyy, Uz, Uzz, Vz, Vzz, Qz, Qzz.

Next, I obtained the expressions for Fxx, Fyy and Fzz which I added and simplified. Later, I equated everything to zero.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 5:59pm On Oct 20, 2013
@benbuks, doubleDx, rhydex247, d citizen, Laplacian and other colleagues, your comments on the solution please
EducationRe: Nairaland Mathematics Clinic by jackpot(f):
Here comes the full solution in PDF format.


already downloaded it? I need your reviews
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 5:46pm On Oct 20, 2013
^ cheesy



No, am just curious to know how many sheets/pages it took you, and not really you posting it.

Is it up to 10?
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 5:24pm On Oct 20, 2013
Laplacian: first i need to point out 2 u dat in PDE one can take d differental of an eqn b4 proceedin 2 d limt witout fear of error...it is rigorous & not an assumption...wit our former notation; now x=uvsinq, y=uvcosq, z=0.5(u^2-v^2), like b4,
Fx=Fu*Ux+Fv*Vx+Fq*Qx...to get Ux, Vx, and Qx we take d differential of d transformation equations; first we take Log of x=uvsinq,
Logx=logu+logv+logsinq, let d denot delta, so dat
1/x*dx=1/u*du+1/v*dv+1/sinq*cosq*dq, divide thru by dx and proceed 2 d limt;
1/x=1/u*Ux+1/v*Vx+cotq*Qx, similarly for y=uvcosq,
logy=logu+logv+logcosq,
1/y*dy=1/u*du+1/v*dv-1/cosq*sinq*dq, divide thru by dx but this time partial derivativ of y w.r.t.x is zero since x and y are independent variables;
0=1/u*Ux+1/v*Vx-tanq*Qx...again for z=0.5(u^2-v^2),
dz=udu-vdv, dividin by dx;
0=uUx-vVx...from d 3 eqns above solve 4 Ux, Vx and Qx...in d eqns above, divide, respectively, by dy and dz to obtain Uy, Vy, Qy and Uz, Vz, Qz...substitute and differentiat Fx,Fy,Fz respectively...u 'll obtain ur answer as i 've done here after simplification...
well, the only lil' harmless mistake is the bolded, cos you swapped the definitions of x and y. wink apart from that, your method is correct so far.

Why not, for fun-sake, complete the solution? I really want to know whether the solution will be shorter wink
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 3:35pm On Oct 20, 2013
cconcept: still waiting for a general to respond
na advanced program be that. I attended a workshop on the sister program SCILAB, but I must say, I don forget the thing sef. I'd advise you google MATLAB User Groups.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 3:32pm On Oct 20, 2013
benbuks: @jackport..shr d link 2 ur solution,or wot do u think..?
acknowledged, Sir. Will do that soon. Let first see what Laplacian's have got! wink

@Laplacian
let's go there. Hope you won't demand ransom first lipsrsealed

post your solution na, pls wink kiss
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 2:46pm On Oct 20, 2013
@Laplacian

am happy. Post the solution, please.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 2:05pm On Oct 20, 2013
hod898: Its simple! Here it goes:
S=UT + 1/2(AT^2)

Make t the subject of formula. Hehe. cool
na this yeye subject of the formula (quadratic equation in "t" solutioned)question you wan take use put confusion as you insinuated?

SMH.
EducationRe: Nairaland Mathematics Clinic by jackpot(f):
Ok, fellow STARRED generals.

As regards to my question, I got the Cartesian-Paraboloidal transformation equations and I knew that Laplace equation have its equivalent in other curvilinear coordinates(like Spherical, Polar, Cylindrical coordinates, etc). So, I decided to obtain the equivalent of the Laplace's equation in Paraboloidal coordinates. I did and I posted it here. So, I have actually attempted that question, and I got the answer.

I posted the question here for a purpose. Not that I wanted to test us. No, not that. I wanted to see how others will solve it.

Reason?

My solution was a 10-paged CRACKER. Are you kidding me? Should that be the only way? Isn't there another shorter method? So, thats why I posted it.

Now, I can share the solution, but I must say, I got it typed in PDF format.

So, fellow generals benbuks, DoubleDx, d citizen, Richiez, etc. decide. Can one upload PDF here, and should I?
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:03am On Oct 20, 2013
d citizen:
The five star general back online.
Thank God dat i have jst fully recovered from acute fever and fully ready to make contributions.
@d citizen

Thank God that you fully recovered. While you were away, Sire, we your boys and girl couldn't resolve this. So we said make we wait for our only 5 STAR Math General to helep us scatter am.
jackpot: [color=indigo]dear Math Generals, pls help me with this little problem.


[size=16pt]By using the Cartesian-paraboloidal coordinate transformation equations:
(x=uv sin φ, y=uv cos φ, z=1/2(u2-v2),
show that the 3-dimensional Laplace's equation
Fxx+Fyy+Fzz=0
reduces to
1/(u2+v2) (Fuu+Fvv+ 1/u Fu+1/v Fv)+1/(u2v2)Fφφ = 0.[/size][/color]
Expecting your answer, Sire! cheesy
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 10:21pm On Oct 19, 2013
Alpha Maximus: ....haha!! Doubledx is a disappointment!! grin....and mind you, I didn't request for his cgpa coz of corrections, I did it coz he said I was a math novice...get your facts right dude and mind your business@dekins88 undecided
Alpha Maximus, if you desist from posting here, we will understand. To tell you the truth, you still have a very long way to catch up in Mathematics. We know you have every right to comment wherever you want, but you see, with what I've seen, your commenting here is risky and you run the risk of infecting the unsuspecting Jambites among us with your wrong solution-right answers. Its not actually mostly your fault since you only teach and believe whatever was shoved down your throat by whom you called teachers, coupled with the fact that you dont know that the solutions are actually wrong.

I am saying this with lots of love. Cheers!
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 10:50am On Oct 19, 2013
doubleDx: You manipulated the law of log and you are here trying to justify what you did? That your answer is correct doesn't mean your workings is!



If I'm to mark the above by method, you might get some points because your 1st 3 steps are correct but the emboldened part is where you fumbled. It's where you showed that you are a Math Captain that should be demoted to the rank of a Sergent grin Lol
lols. You've gat jokes wink

my guy Maximus na Charge and Bail lawyer Mathematician cheesy grin grin grin

na 2 and half-star maths general grin
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 10:44am On Oct 19, 2013
doubleDx: I started solving it a few days ago but did not finish. I will try to get it done and post it. Take care
ok, no probs. I'll be waiting.

Where is our self-acclaimed "Only 5 STAR Maths General" d citizen ?

He should come and post his solution ooo cheesy

@benbuks
bros, do something na. wink 4 STAR no be beans cheesy
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 7:05pm On Oct 18, 2013
Alpha Maximus: Taking log of both sides, we have:
Log2^x=Log4x
Xlog2=log4+logx
Logx=xlog2-log4
Canceling logarithm, we have:
X=2x-4

2x-x=4
X=4
undecided
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:46pm On Oct 18, 2013
doubleDx: Lol, I see una! grin Jackpot ko Jackport ni ! Una dey test us ni?
no ooo. No mind benbuks oooo. He is a praise-singer. :-D How can I test my baba. I have actually learnt a lot from you lipsrsealed

i no sabi that kweshun sef. My problem is how to get the first partial derivatives like Ux, Uy, Uz. I know the chain rule well, but what and what should I substitute as my Ux, Uy, Uxx and co?

Teach me na, pls
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:41pm On Oct 18, 2013
Laplacian: ...Hello Jackpot, i am more than glad 2 recieve dis correction from u, sometin i'd neva thought of...i should infer dat u're by no means an amature. 4 if u were, u wouldn't 've debugd dat intricate error...now, usin d same notation,
Fu=Fx*Xu+Fy*Yu+Fz*Zu...u can make direct differentiation now...Fuu, Fv, Fvv, Fq and Fqq may then b obtaind similarly...u'll have three equations, i.e Fuu, Fvv and Fqq, in three variables; Fxx, Fyy and Fzz which u can solve (preferably by Matrix) and make substitution into Laplace equation and simplify...i know u posses a shorter method...if u do, relate it to us....tanx
Applying the chain rule and product rule on Fu to get Fuu, we will have

Fuu=(Fx *Xu+Fy Yu+Fz*Zu)u
=(Fx *Xu)u +(Fy *Yu)u +(Fz*Zu)u
=Fx * Xuu +(Fxx Xu +Fxy Yu + Fxz Zu)+
Fy * Yuu+ (Fyx Xu +Fyy Yu + Fyz Zu)+
Fz * Zuu + (Fzx Xu+ Fzy Yu + Fzz Zu)

so, you see, there are nine variables, not 3 as you suggested.

The variables are Fx, Fy, Fz, Fxx, Fxy=Fyx, Fxz=Fzx, Fyy, Fyz=Fzy, Fzz.

so its no longer 3 equations in 3 unknowns.

Besides, how will you make Fv and Fu appear in the solution? Or, how will you sieve out Fxx, Fyy and Fzz and ignore Fx, Fy, Fz, Fxy and others?

This reverse approach may likely hit a dead end.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 6:06pm On Oct 18, 2013
benbuks: Still waitin 2c solution 2 jackport's enigma.
yeah, me too.

Where is my DoubleDx, Richiez and our 5 Star General d citizen?

I have been refreshing this page since for DoubleDx's expected solution.
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 2:20pm On Oct 18, 2013
Laplacian: i use Fx to denot derivatv of F w.r.t.x....let q denot phi now
Fx=Fu*Ux+Fv*Vx+Fq*Qx, now
Ux=1/Xu=1/(v*sinq), similarly, Vx=1/(u*sinq), Qx=1/(uv*cosq)....substitut into the eqn for Fx and differentiat partially w.r.t.x again to get Fxx....do the same for Fyy and Fqq, then put the result in the Laplace eqn, simplify and get the result...the result is too weird to b includd here...
Hi Laplacian.

I may have to comment on the bolded.

You see, even though it works like that in ODE(ordinary differential equation) where we say dy/dx=1/(dx/dy), it doesn't work like that in PDE(partial differential equation).

As an example, consider the polar coordinate transformation equations: x=r cos T, y=r sin T, where we use T to denote theta.

Now xT=-r sin T.

But observe that
tan T= y/x implies sec2 T *Tx= -y/(x2)
implies Tx= -y/(x2) * cos2 T
=-y/(x2) * (x/r)2
=-y/(r2)
=-(sin T)/r

so you see, xT=-r sin T

Tx=-(sin T)/r

clearly Tx is not equal to 1/(xT ).


Thanks for attempting it though. I am happy someone actually wanted to put a smile on my face kiss cool
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 8:58pm On Oct 16, 2013
doubleDx: I'm on it, maybe I'll post tomorrow! Where is our 5 Star General (d citizen); I was waiting for you to post first. You are the Boss, Sire! @Jackpot, are you a Mathematician/Mathematics Student or an Engineer/Engineering Student?
***Happy Mood Activated!!!*** kiss

maths student
EducationRe: Nairaland Mathematics Clinic by jackpot(f): 2:42pm On Oct 15, 2013
d citizen:
. . . Jacpot, u are welcome on board. Am the one and only five star math general
Hi d citizen, good to know you are a 5-STAR Maths general. Pls help me with the solution to this problem that I posted earlier
jackpot: dear Maths generals, pls help me with this little problem.


[size=14pt]By using the Cartesian-paraboloidal coordinate transformation equations:
(x=uv sin φ, y=uv cos φ, z=1/2(u2-v2),
show that the 3-dimensional Laplace's equation
Fxx+Fyy+Fzz=0
reduces to
1/(u2+v2) (Fuu+Fvv+ 1/u Fu+1/v Fv)+1/(u2v2)Fφφ = 0.[/size]
any clue to solving it will also be appreciated. thanks!

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