₦airaland Forum

brachistochrone problem: Suppose that there is a
rollercoaster. There is point 1 and point 2 . Point 1 is at the higher place when compared to the point 2, so the rollercoaster rolls down from
point 1 to point 2. Assuming no friction, we want to
build a rollercoaster path from point 1 to point 2, so
that the rollercoaster will reach point 2 from point 1 in
shortest time. Find the curve dat would help us achieve this?

This question is tricky, emmm, my fellow engineers lets tackle this one.

, never liked differential equations, I only attempt if something is at stake, lol. I find integration and differention fun, remember so pritty funny questions, say you are given a base functions dat generate solids by finding the integrals, you are to lets say find a resulting volume by subtracting a cone from a cylinder...school days...fun... Do you guys play chess? I think it helps. Plus the pritty girls

doubleDx: Good idea, I think I'll post some questions today or tomorrow too. Where is our five-star General?

I'm a three-star General oh

You are modest, if anyone should be given five stars it's you. What happened on Sunday was a joke dat went bad, I salute my general DoubleDx...

That will make for an interesting zoo home.

Is dat 190 reaching out for chestnuts in the snow? Wow talking about die-hards...

^^^ Nice story, reminds me of cinderella and the little glass slipper, nice...

obadiah777: MY PARENTS WERE ARRANGE MARRIAGE. MY DAD WAS IN ENGLAND. AND HIS FAMILY SENT A NIGERIAN WOMAN TO HIM OVER THERE TRUE STORY

Same with my parents too, only dat my dad was a student in Italy at the time. Mum is late now, but she was the best cook in the world...

Richiez: Doubledx Ride on, you're a star
@Ositadima1 common show dis chic what you got!

lol, h i p for the hip, hippo hippo for the hip hippopotamus...

Let it go...bro

doubleDx: Oh, all the questions you've been solving here is so you can gain popularity and get chics online? Well, some of us are married and we do this to help people and not for some e-chics

lol, what did I do to you this Sunday

doubleDx: Lol, what I started? When did we start doing that on this thread? That's quite funny! If that's the case then I think only the op should answer questions on here. Na wa oh

Well, I'm helping just like you are doing so when I get home I'll help her finish the b part.

Yes sir!

doubleDx: Lol bro, I'm typing and walking help her finish the b part. Carry on bruv, I'm with you all the way

brother me dey walka too, branch some where and end what you started.

doubleDx: Questiob 1 a

[ 2 3 7]
[(x - y) 1 3]
[(x+y) 3 5]

A matrix A is said to be symmetric if A equals K transpose. i.e A => A^T which means that if we interchange rows and columns of A, the matrix remains
unchanged.

:. If the above matrix is A, then K transpose will be =>

[2 x-y x+y]
[3 1 3]
[7 3 5]

Looking at the two matrices, A and A^T. The number on the first row second column of A^T is given by the expession (x - y) which equals 3 in the matrix A.

Hence x - y = 3 ......(1)

Also, the number on the first row third column of A^T is given by the expression (x + y) which equals 7 in the matrix A.

:. x + y = 7 .....(2)

Adding equation (1) and (2) yields=>

x - y = 3
x + y = 7
2x = 10
x = 5

subtitute x in equation (1)

5 - y = 3
y = 5 - 3
y = 2

:. x = 5 and y = 2.

See babe I wan chike..., u don quickm answer finish, finish it up joo...

SpicyMimi: I NEED YOUR ASSISTANCE GUYS?!! You dont know how happy i am to find this thread, feeling so relaxed now! Please help me solve the following questions on Matrix.

The Matrix of units of products produced by Daddy K cream factory in three shifts is given:
(2 3 7)
( X-Y 1 3)
(x+Y 3 5)
You are required to determine:
(a) Rhe values of x and y, if Matrix A is Symmetric.
(b) The gross revenue vector (AP) for each product, if the price $P per unit of the product is given by the vector P = (45)
(30)
(55)

please i need the solution before tomorrow!!! Pleaseeeeeeee!!!

You want us to do your homework for you, while u dey chill out abi?

doubleDx: @Osita, I think you didn't get the question properly, it says we should differentiate wrt to y and not x. You did a good job but you solved yours wrt x. That explains why your first derivative differs from mine.

There is no need to removing your workings. It's perfect if we are to differentiate with respect to x. That could help some folks, just indicate that you are differentiating wrt x then check the one wrt y. 1heart bro.

ha haha, my bad...

tonardo: Tv receiver for sale
Price: 15.000
tel: 08021438880
location... Okota. Isolo~oshodi LGA lagos...
Serious buyer pls

I have one for sale too, same price. I stay in portharcourt.

arctan(y/x)=v so, tan(v)=y/x I am going to manipulate with sin^2(v)+cos^2(v)=1

Now, dividing sin^2(v)+cos^2(y/x)=1 by cos^2(v)... u know sin^2(v)/cos^2(x)=tan^2(v) and 1/cos^2(v)=sec^2(v)
1+tan^2(v)=sec^2(v)

So, sec^2(v)=1+(y/x)^2
recalling arctan(y/x)=v
sec(arctan(y/x))=sec(v)
square both sides sec^2(arctan(y/x))=sec^2(v)=1+(y/x)^2
sec^2(arctan(y/x))=1+(y/x)^2

now, using chain rule and taking partial derivative of both sides with respect to x we have...

∂[sec^2(arctan(y/x))]/∂x=∂[1+(y/x)^2]/∂x

∂[arctan(y/x))]/∂x*2[sec^2(arctan(y/x))]*tan[(arctan(y/x)]*(-(y/x)^2)=-2*y^2/x^3

now, tan[(arctan(y/x)]=y/x
sec^2(arctan(y/x)=1+(y/x)^2

substituting back

∂[arctan(y/x))]/∂x*2*[1+(y/x)^2]*(y/x)*(-(y/x)^2)=-2*y^2/x^3

∂[arctan(y/x))]/∂x*[1+(y/x)^2]*-2*y^3/x^3=-2*y^2/x^3

∂[arctan(y/x))]/∂x*[1+(y/x)^2]=y

∂[arctan(y/x))]/∂x=y/[1+(y/x)^2]

second partial derivative

∂^2[arctan(y/x))]/(∂x)^2=∂[y/[1+(y/x)^2]/∂x using chain rule again...
p
∂^2[arctan(y/x))]/(∂x)^2=-y[1+(y/x)^2]^(-2)*-2*y^2/x^3

∂^2[arctan(y/x))]/(∂x)^2=2xy(x^2+y^2)^2

DoubleDx there is no minus in the final solution, check again

lordZOUGA: writing a full file manager or commercializing?

I say go for it. I think there is a market, with people having lots of data on there hds, besides people like me who are totally messy would like this. Check this link www.techsupportalert.com/best-free-file-manager.htm, there are a couple of file managers, you may steal a look at them. IMO don't reinvent a wheel add tube and tire though.

lordZOUGA: so you want me to write a full blown file manager? Commercialize...? Interesting thought

Before nko?

lol, hey goodnight.

spikes C: #falls inside GP tank

How you go take come out ni

190 u are a lucky son of a gun, was into taekwondo, karate, and jiu jitsu. I'd kick off all your teeth, but Jay... Jay would hate me for dat... I am not engaging you.

Now, Hip Hip Hurray!!! My thread crossed a 1000 hits, thank you, thank you, thank you, thank you, you are so kind

***In my deepest Igbotic accent*** KMT!!!!

It was kinda fun, I'd kiss ur t.its with relish!!!
Chao

Flytefalls: Dude, check your emails kmt. This nl convo thing is long.

You mean you are giving up on me? Jay... Fine
It's almost 1000 views, my very first...

Black bags Pardon my ignorance, I live in Africa anyway... , what's dat?

Flytefalls: Haha! Keep trying

Sledge? We aren't in the 18th century . It's black bags now . But I won't be sledging. It's war

Snow throwing match?

Flytefalls: Snow!!!!! Where is my uncle, I want to fight him! #revenge

But dat is awesome, can I see ur pix? The one with you in a sledge... beautiful with a pink tinge on the tip of ya nose... snow white would be really envious.

lordZOUGA: if and when it blows up

Hey, don't be pessimistic joo, there are similar programs in the market, you need to study them, reverse engineer them if possible , and impliment in urs while putting more value, yeah u need sponsors dats the hard part...

lordZOUGA: yeah you are making sense. Infact I was going to include it as an update but I have not tested the algorithm I thought up for it.. So I let it lie.. I got the idea because the way TV series (season movies) were scattered across my system was driving me crazy.

Cool, when this thing blows up, I would like to work for you... I am learning python 2 and 3 in my spare time.

hi

Richiez: Excellent work! General DoubleDx

Richiez... you have the qualities of a leader.

This is good, I see it growing up into something big.I did like to sponsor but I got no dough now, but regarding sorting beyond file extensions, what of making it look up a user prespecified sequence of characters(number tag, a particular word) in d file title. I work with drawings, and I tend to save my stuff on my desktop, having all my .dwg sorted into series would be nice, like all the DEFU series in one folder...
You may also push it further and let it scan this files and sort base on content, like I have lots of pdfs in a folder and I want them sorted based on a phrase or word withing the pdfs. Lol, I don't know if I am making sense...

Saiyonara