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Re: Nairaland Mathematics Clinic by MaxGraviton: 5:05am On Aug 03, 2015
Geofavor:

I was being precise with the topic/question being argued, not maths in general. Not numbers.

You said earlier that, 5C0 is invalid in this aspect of maths(permutation n combination) because of the comparison of an actual number with zero. You said they shouldn't be compared because 0 is valueless.

I never said a computation of 5C0 was invalid. I was only pointing out that accounting for that which was not present was incorrect. (Of course I've been proved wrong). I now see my mistake.

Geofavor:

Which was why i reminded you that in this case, it isn't. Why? Because factorial is involved!

And I'm still making it clear that, if you want to prove to anyone that 0 has value, FACTORIAL of 0, is not a way. Whether in combination & permutation or in Kangaroo Maths, (lools) .
5C0 = 5!/(5 - 0)! 0![/quote]
Re: Nairaland Mathematics Clinic by agentofchange1(m): 7:09am On Aug 03, 2015
possibilita:
yes that's hw 1c is written

ok here

Q1c
y' = (3y2 +2xy)/(2xy+x2 ).. ......(B)

Set y=vx. V= y/x

=> y'=xv' +v ...(E)

Equate with (B) above
We have

Xv'+v= [3(vx)^2 +2x(vx)]/[2x(vx) +x^2]

=( 3x^2 v^2 +2x^2 v )/(2x^2 v +x^2)

Pull out ' x^2 '

=> xv' =(3v^2 +2v) /(2v+1). - v

= xv '= (3v^2 +2v -2v^2 -v)/(2v+1)

Xdv/dx = (v^2 +v) /(2v +1)

=>( 2v+1)dv/(v^2 +v) = dx/x

Taking integral on both sides yields

In(v^2 +v)=lnx + lnC

Or v^2 +v = CX

Since y/x = v

hence we have

=(y/x)^2 + (y/x) = CX


ii)

y' = y/x + xsin(y/x)

Let vx=y , v= y/x

Xv'+ V = y'

We get

xv' +v = v + xsinv .

Or v'= sinv

By separating variables

=> (1/sinv)dv = dx

On integrating both sides

=> In[tan(v/2)] = x+c

Or tan(v/2)= exp(x+c)

Or v/2 =arctan[exp(c+x)]

Or v= 2arctan[ e^c *e^x]

Since v=y/x

=>y/x = 2arctan(Ke^x)

(Where k= e^c)

Hence

Ans:y=2xarctan(Ke^x)



That's it man.

3 Likes 1 Share

Re: Nairaland Mathematics Clinic by possibilita(m): 7:17am On Aug 03, 2015
agentofchange1:

ok here
thank u very much bros
Re: Nairaland Mathematics Clinic by agentofchange1(m): 7:24am On Aug 03, 2015
possibilita:
thank u very much bros

UWC man

1 Share

Re: Nairaland Mathematics Clinic by agentofchange1(m): 7:34am On Aug 03, 2015
m kinda busy now, remaining solutions might come later ,
av solved them already , just 2uplaod ...


or my bosses in d hus can do that ,


#Slalom.
Re: Nairaland Mathematics Clinic by Antoinne: 8:54am On Aug 03, 2015
agentofchange1:


ok here
Good job, agentofchange1.
Re: Nairaland Mathematics Clinic by Antoinne: 9:16am On Aug 03, 2015
agentofchange1:


ok here
There seems to be a mistake in the first two lines in the first picture with y2. Would affect the final answer significantly.
Re: Nairaland Mathematics Clinic by agentofchange1(m): 9:21am On Aug 03, 2015
Antoinne:

There seems to be a mistake in the first two lines in the first picture with y2. Would affect the final answer significantly.

oh yeah, my bad , just noticed that now ...will upload corrected solutions sir

thanks once again.
Re: Nairaland Mathematics Clinic by agentofchange1(m): 12:16pm On Aug 03, 2015
jackpot:
Find the inverse laplace transform of 1/(s^5+a^5)

tags: Laplacian, agentofchange1, doubleDx, dejt4u, Alphamaximus, jaryeh

considering the denominator

s^5 +a^5

in general

xn + yn

=(x+y) £ yk* x(n-1-k) for k=0,1 2, . . . ,(n-1)

where £ = sigma (summation)

does that ring a bell?. I know say you na Prof.
Re: Nairaland Mathematics Clinic by Laplacian(m): 12:28pm On Aug 03, 2015
Antoinne:

I took it you'd understand my little explanations.
Let's get the first part sorted. Look at the attached pic.

After resolving the elemental distances, dx & dy and multiplying. Follow the extension down to y = 1-x at z=0, you'll see that the distance dx on the other side is not exactly parallel to the distance you just resolved. I marked it with "A". There's still some kind of triangle there, showing that you elemental distance is not representative of the surface.

If that's too difficult, look at the basic 2D triangle below it. If you took a small portion on the x-axis called dx. Do you think it'll be equal to the length marked "A" on that same triangle merely by tracing it up?

It's the same thing happening on that surface above. You get it?
yes, i think they will b equal. This new diagram luks beta
Re: Nairaland Mathematics Clinic by MaxGraviton: 12:35pm On Aug 03, 2015
Please, This is really Urgent. Someone should please help me with the name of that Maths textbook popularly known as BONDE. . . Bonde is the name of the person that wrote the book. But Please I need the actual name. Thanks.
Re: Nairaland Mathematics Clinic by Laplacian(m): 12:38pm On Aug 03, 2015
In spherical co-ordinate, with standard notation, is it not logical to expect d elementary area on d sphere to be;
dS=r2d@d¤?
Why is it necessary to resolve in the xy plane to have;
dS=r2sin@d@d¤.
Note; @ is theta, ¤ is phi
Re: Nairaland Mathematics Clinic by Antoinne: 5:01pm On Aug 03, 2015
MaxGraviton:
Please, This is really Urgent. Someone should please help me with the name of that Maths textbook popularly known as BONDE. . . Bonde is the name of the person that wrote the book. But Please I need the actual name. Thanks.
Pure Mathematics for Advanced Level
by B.D. Bunday & H. Mulholland
Re: Nairaland Mathematics Clinic by Antoinne: 5:04pm On Aug 03, 2015
Laplacian:

yes, i think they will b equal. This new diagram luks beta
Come on! No, they will not be equal. Look at the diagram again. "A" will have to be

A.cos(phi) = dx. Not A = dx.

You see it?
Re: Nairaland Mathematics Clinic by MaxGraviton: 5:47pm On Aug 03, 2015
Antoinne:

Pure Mathematics for Advanced Level
by B.D. Bunday & H. Mulholland


May God Bless Your Generation. . . thanks. grin grin
Re: Nairaland Mathematics Clinic by jackpot(f): 10:52pm On Aug 03, 2015
agentofchange1:

considering the denominator
s^5 +a^5
in general
xn + yn
=(x+y) £ yk* x(n-1-k) for k=0,1 2, . . . ,(n-1)
where £ = sigma (summation)
does that ring a bell?. I know say you na Prof.
**in a kid's voice**
Broda, finish it
Re: Nairaland Mathematics Clinic by Laplacian(m): 5:52am On Aug 04, 2015
Antoinne:

Come on! No, they will not be equal. Look at the diagram again. "A" will have to be

A.cos(phi) = dx. Not A = dx.

You see it?
u'r right, they form a right angled triangle...maybe i shoul just take a rest!
Re: Nairaland Mathematics Clinic by jackpot(f): 6:01am On Aug 04, 2015
please, help me out.
1. Consider the parabola: x=(3-2y)(4y+3). Obtain i. Directrix equation ii. Focus iii. Vertex iv. Length of it's latus-rectum


2. Consider the hyperbola 4x^2-4x-y^2+6y+28=0. Obtain i. Eccentricity ii. Foci iii. Vertex iv. Centre v. The Length of it's semi-latus rectum vi. It's asymptotes.

tags: agentofchange1, dejt4u, Laplacian, Antoinne, Karmanaut, doubleDx, etc
Re: Nairaland Mathematics Clinic by Antoinne: 6:17am On Aug 04, 2015
Laplacian:

u'r right, they form a right angled triangle...maybe i shoul just take a rest!
I like your inquiring mind though. Naturally i wouldn't have done it the way you intended to do it. Most textbooks wouldn't, since it's just easy to use the dot product. But your approach to understanding it from "first principle" is commendable.
Still give it a try when you free. Just think about resolving the elemental area and not the individual distances.
Let me see if there's an approach to resolving the individual distances and I'll get back.

1 Like

Re: Nairaland Mathematics Clinic by jackpot(f): 4:03pm On Aug 04, 2015
Please help me out

Solve the functional equations below for f(x) and g(x) respectively:

1. f(x)-f(-x)= - 1/x


2. g(x)-g(-x)=-1/x, given that g is odd.





tags: agentofchange1, dejt4u, STENON, AmazingAngel, Antoinne, Laplacian, Karmanaut, doubleDx, etc
Re: Nairaland Mathematics Clinic by Laplacian(m): 4:22pm On Aug 04, 2015
jackpot:
Find the inverse laplace transform of 1/(s^5+a^5)

tags: Laplacian, agentofchange1, doubleDx, dejt4u, Alphamaximus, jaryeh
let kn=e2#ni/5, n=1,...,5 where # is pi
then,
1/(s^5+a^5)=product1/(s-akn)....resolve using partial fraction, cover-up rule (all factors are distinct) e.t.c
Re: Nairaland Mathematics Clinic by Nigeriatraining: 4:44pm On Aug 04, 2015
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Re: Nairaland Mathematics Clinic by Laplacian(m): 5:06pm On Aug 04, 2015
jackpot:
Please help out

Solve the functional equation below for f(x):

1. f(x)-f(-x)= - 1/x

2. f(x)-f(-x)=-1/x, given that f is odd.


tags: agentofchange1, dejt4u, STENON, AmazingAngel, Antoinne, Laplacian, Karmanaut, doubleDx, etc
if f(x)-f(-x)=-1/x then f(x) can neither be an even function nor have an even part, otherwise we have f(-x)=f(x) or f(x)-f(-x)=0, plug into d given eqn we have 0=-1/x, takin inverse makes x undefined. If f(x) is odd then f(-x)=-f(x), hence 2f(x)=f(x)-f(-x)=-1/x
Re: Nairaland Mathematics Clinic by Youngsage: 5:08pm On Aug 04, 2015
O boy!
Re: Nairaland Mathematics Clinic by jackpot(f): 6:01pm On Aug 04, 2015
Laplacian:

let kn=e2#ni/5, n=1,...,5 where # is pi
then,
1/(s^5+a^5)=product1/(s-akn)....resolve using partial fraction, cover-up rule (all factors are distinct) e.t.c
Now, this is what I call a sexy solution. Introduce i but make the solution look compact. Unlike the other solution that is complex upon complex with all the known operations (imaginary, plus, minus, division, multiplication, square root, so many lines cheesy , etc) in mathematics coming in a single solution.

Well done Sir

1 Like

Re: Nairaland Mathematics Clinic by jackpot(f): 6:11pm On Aug 04, 2015
Laplacian:

if f(x)-f(-x)=-1/x then f(x) can neither be an even function nor have an even part, otherwise we have f(-x)=f(x) or f(x)-f(-x)=0, plug into d given eqn we have 0=-1/x, takin inverse makes x undefined. If f(x) is odd then f(-x)=-f(x), hence 2f(x)=f(x)-f(-x)=-1/x
Well, unlike integers that are either even or odd, a function may be neither even nor odd, eg h(x)=sin x-cos x, x+x2.
Also, functions may have non-integral exponent, eg h(x)= xe=x2.718281828. . . or p(x)= £ x, where £ is the Gamma function or q(x)=x2/7.

Now, my question is: how are we sure that there are no neither-even-nor-odd functions f satisfying the equation:
f(x)-f(-x)= -1/x ?


tags: Laplacian, agentofchange1, Laplacian wink , agentofchange1, doubleDx, Antoinne, dejt4u, AlphaMaximus, Laplacian grin etc
Re: Nairaland Mathematics Clinic by Antoinne: 6:58pm On Aug 04, 2015
jackpot:
please, help me out.

[b]1. Consider the parabola: x=(3-2y)(4y+3). Obtain
i. Directrix equation
ii. Focus
iii. Vertex
iv. Length of it's latus-rectum

Parabola of x = (3-2y)(4y+3)
x = 12y + 9 - 8y2 - 6y
x = 9 + 6y - 8y2

Parabola is about y, since y has two values.
We can treat this as a mirror y = 9 + 6x - 8x2, and then invert the mirror at the solution, if x is easier to work with.

anyways, for a parabola y = ax2 + bx + c with a focus at p distance above the vertex V(h,k).
dy/dx = 2ax + b. At the vertex, you have the least variation, so dy/dx=0
2ax + b = 0
x = -b/2a, this should correspond to h.

y = ax2+bx+c at x = -b/2a, k
k = (4ac - b2)/4a

Assuming parabola at origin and following definition 4py = x2
Move parabola to right of xy plane so that vertex is V(h,k)
4p(y-k) = (x-h)2
Relating coefficients produces p = 1/4a, (focus)

Latus-rectum is length across focus.
if Parabola at origin (0,0)
4py = x2
with y = p on curve
x2 = 4p.p = 4p2
x = 2p

Length of latus-rectum
2.x = 4p

Now, from earlier equation y = 9 + 6x - 8x2 (mirror)
a = -8, b = 6, c=9

focus, p = 1/4a = 1/(4*-8 )
=-1/32

Vertex, V(h,k)
h = -b/2a = -6/(2*-8 ) = 3/8
k = (4ac - b2)/4a = 81 / 8

Length of latus-rectum = 4p
=abs(4.(-1/32)) = 1 / 8

Directrix equation: y = 325/32, i.e. (1/32 + 81/8 )

We can now go ahead and mirror our solution by just changing all x to y, and y to x
i. Directrix equation: x = 325/32
ii. Focus: -1/32
iii. Vertex: V(81/8, 3/8 )
iv. Length of it's latus-rectum: 1/8

1 Like

Re: Nairaland Mathematics Clinic by Laplacian(m): 7:18pm On Aug 04, 2015
jackpot:
Well, unlike integers that are either even or odd, a function may be neither even nor odd, eg h(x)=sin x-cos x, x+x2.
Also, functions may have non-integral exponent, eg h(x)= xe=x2.718281828. . . or p(x)= £ x, where £ is the Gamma function or q(x)=x2/7.

Now, my question is: how are we sure that there are no neither-even-nor-odd functions f satisfying the equation:
f(x)-f(-x)= -1/x ?


tags: Laplacian, agentofchange1, Laplacian wink , agentofchange1, doubleDx, Antoinne, dejt4u, AlphaMaximus, Laplacian grin etc
# with functions that are neither even nor odd, one can often find each part seperately and add them together.
# functions in which the variables are in integral powers are often called algebraic functions, and the theory of functional equations is usually restricted to this class of functions...elliptic functions, theta functions, mathieu functions e.t.c are not elementary functions and exhibit very cmplx properties which are unfamiliar and when incorperated into this subject makes it irrelevant and uninteresting
# there is no claim as to the uniqueness of a solution to a functional equation, since there maybe other solutions depending on the available properties and method of solution used
Re: Nairaland Mathematics Clinic by Antoinne: 7:25pm On Aug 04, 2015
jackpot:
Well, unlike integers that are either even or odd, a function may be neither even nor odd, eg h(x)=sin x-cos x, x+x2.
Also, functions may have non-integral exponent, eg h(x)= xe=x2.718281828. . . or p(x)= £ x, where £ is the Gamma function or q(x)=x2/7.
Now, my question is: how are we sure that there are no neither-even-nor-odd functions f satisfying the equation:
f(x)-f(-x)= -1/x ?

I think you right. We cant know unless otherwise stated. And I think you provided a solution already if f(x) were odd.

1 Like

Re: Nairaland Mathematics Clinic by Laplacian(m): 7:38pm On Aug 04, 2015
Antoinne:


Parabola of x = (3-2y)(4y+3)
x = 12y + 9 - 8y2 - 6y
x = 9 + 6y - 8y2

Parabola is about y, since y has two values.
We can treat this as a mirror y = 9 + 6x - 8x2, and then invert the mirror at the solution, if x is easier to work with.

anyways, for a parabola y = ax2 + bx + c with a focus at p distance above the vertex V(h,k).
dy/dx = 2ax + b. At the vertex, you have the least variation, so dy/dx=0
2ax + b = 0
x = -b/2a, this should correspond to h.

y = ax2+bx+c at x = -b/2a, k
k = (4ac - b2)/4a

Assuming parabola at origin and following definition y = 4px2
Move parabola to right of xy plane so that vertex is V(h,k)
4p(y-k) = (x-h)2
Relating coefficients produces p = 1/4a, (focus)

Latus-rectum is length across focus.
if Parabola at origin (0,0)
4py = x2
with y = p on curve
x2 = 4p.p = 4p2
x = 2p

Length of latus-rectum
2.x = 4p

Now, from earlier equation y = 9 + 6x - 8x2 (mirror)
a = -8, b = 6, c=9

focus, p = 1/4a = 1/(4*-8 )
=-1/32

Vertex, V(h,k)
h = -b/2a = -6/(2*-8 ) = 3/8
k = (4ac - b2)/4a = 81 / 8

Length of latus-rectum = 4p
=abs(4.(-1/32)) = 1 / 8

Directrix equation: y = 325/32, i.e. (1/32 + 81/8 )

We can now go ahead and mirror our solution by just changing all x to y, and y to x
i. Directrix equation: x = 325/32
ii. Focus: -1/32
iii. Vertex: V(81/8, 3/8 )
iv. Length of it's latus-rectum: 1/8
Assuming parabola at origin and following definition y = 4px2?
Re: Nairaland Mathematics Clinic by Antoinne: 7:50pm On Aug 04, 2015
Laplacian:

Assuming parabola at origin and following definition y = 4px2?
Corrected. thanks
Re: Nairaland Mathematics Clinic by Nobody: 7:54pm On Aug 04, 2015
jackpot:
Unlike the other solution that is complex upon complex with all the known operations (imaginary, plus, minus, division, multiplication, square root, so many lines cheesy , etc) in mathematics coming in a single solution.
grin

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