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#401 Re: Help Me ! » Some Polynomial Problems » 2017-02-07 23:55:36

bobbym wrote:

Hi;
I am suffering from a migraine so I am a bit weak....

What is migraine?

#402 Re: Help Me ! » Logical question s » 2017-02-02 01:51:19

Hi here are all the answers.

#405 Re: Help Me ! » Contestants and stamps » 2017-01-26 05:18:09

salem_ohio wrote:

The host places one stamp on each of the contestant’s forehead in such a way that each contestant can only see the other stamps, but not his own.

What do you mean by the other stamps? Are they the stamps on the other 2 person's forehead. If that is to be then they will discuss what they could see on the other two person's forehead and then everyone can tell the correct answer.

#406 Re: Coder's Corner » Complex Loop » 2017-01-11 23:36:32

In which programming language do you want the loop program to be written?

#407 Re: Help Me ! » Mathematics » 2017-01-11 23:30:55

hi, the most interesting I find of all series and sequences is the fibonacci series. Hi mesiya do you have any question about them or were you just testing the "post new topic" in this forum. if you have any question plz ask.

Welcome to this forum.

#408 Re: This is Cool » Partial sum formula of a series by recursion » 2017-01-10 01:40:32

Hi, Eulero
The formula is too complicated to remember. It can be remembered much more easily by Implementing Faulhaber's formula. It says,
1ˣ +2ˣ +3ˣ +4ˣ ......nˣ =[1/(1+x)](aB₀nˣ⁺¹+bB₁nˣ+cB₂nˣ⁻¹............yBₓn), where Bₙ is the nth Bernoulli no. and a,b,c,.....y are the consecutive terms of (x+1)th row of Pascal's Triangle.
For e.g.
1¹¹+2¹¹+3¹¹+4¹¹.....7¹¹=(1/12)(1B₀n¹²+12B₁n¹¹+66B₂n¹⁰+220B₃n⁹+495B₄n⁸+792B₅n⁷+924B₆n⁶+792B₇n⁵+495B₈n⁴+220B₉n³+66B₁₀n²+12B₁₁n)
(1+B)ⁿ⁺¹-Bₙ₊₁=0
For e.g.
for,B₁ n=1 so
(1+B)²-B₂=0
⇒1+B₂+2B-B₂=0
⇒1=2B=0
⇒B=-0.5
However in this ( the formula for sums of powers )formula B₂=+0.5

#410 Re: Introductions » Hello. » 2016-12-28 22:48:31

u have written that u have dual personality good and bad.
And your favourite quote is Your best friend is your best rival.

#411 Re: Introductions » Hello. » 2016-12-28 22:43:50

No I promise I didn't google your username. Facebook,man facebook

#412 Re: Introductions » Hello. » 2016-12-28 19:38:26

And you are studying in Muhammadiyah Surakarta University. I'm right no

And you also love manga One Piece.

#413 Re: Introductions » Hello. » 2016-12-27 23:08:30

Hey, do you live in Surakarta ????

#414 Re: Help Me ! » train accelerating » 2016-12-26 22:47:58

Hey, I'm very sorry it was my silly mistake . Abhishek is right. Correct answer is 2/3 ms-²

#415 Re: Formulas » A direct formula for HP » 2016-12-25 23:40:59

Note: Harmonic Progression are the reciprocals of Arithmetic progression. It is in the form 1/a+1/b+1/c+1/d..... , where a,b,c,d,.... are in AP.

#416 Formulas » A direct formula for HP » 2016-12-25 23:38:14

iamaditya
Replies: 5

We know that there are 3 types of progressions Arithmetic, Geometric and harmonic. The Formula for sums of AP and GP are given below:

A.P.→ [n(a1+an)]/2=[n{2a1+(n-1)d}]/2
G.P→ [a1(1-rⁿ)]/(1-r)
where, a1= 1st term
            an=last term
            d= common difference
            r=Common ratio
            n=no. of terms                                                                                                                                  n
So can anyone tell  me a similar direct formula for HP(Harmonic progression) also. And yeah I had found out that ∑   1/k ≈In(n) + γ where,γ= Euler Mascheroni const.
                                                                                                                                                                   k=1                                  ≈ 0.5772156649015.....
Can anyone please prove it.

#417 Re: Introductions » Hello. » 2016-12-25 23:02:56

Hi Monox D. I-Fly, I'm an Indian not an Indonesian. Well, from which country are you???

#418 Re: Help Me ! » train accelerating » 2016-12-25 22:55:15

Hi. I Also agree with thickhead's answer. I solved like this:

v1=v m/s
u1= 0m/s (Starting from rest)
a1=a m/s²

v²=u²+2as
⇒s=(v²-u²)/2a
⇒s1=(v1²-u1²)/2a1
⇒s1=v²/2a

v=u+at
⇒v1=u1+a1t1
⇒(v1-u1)/a1=t1
⇒v/a=t

v2=0 m/s (Stopping at rest)
u2= v m/s
a2= 3a m/s²

v²=u²+2as
⇒s=(v²-u²)/2a
⇒s2=(v2²-u2²)/2a2
⇒s2=(-u2²)/2a2
⇒s2=(-v²)/6a

v=u+at
⇒v2=u2+a2t2
⇒(v2-u2)/a2=t2
⇒-u2/a2=t2
⇒-v/3a=t2

Avg. Speed=Total distance/Total time
=(s1+s2)/(t1+t2)
=v/2

v/2=√(s1+s2)
⇒v/2=v/√(3a)
⇒2=√(3a)
⇒4=3a
⇒a=4/3 m/s²

#419 Re: Maths Teaching Resources » Maths Books » 2016-12-05 22:26:15

Those of my lvl I can do very well others such as questions on trigonometry and those which are not of my lvl I cannot do that. Some others like "interesting information..." needs just a calculator to solve all problems in seconds. Some I think I can do but I (most probably by mistakenly) looked at those answers below and therefore couldn't solve.
Otherwise if finally it is asked how about those questions then I would say "good".

#422 Re: Euler Avenue » Factorials, Hyperfactorials and Superfactorials » 2016-12-03 22:34:58

Neil Sloane and Simon Plouffe defined a superfactorial in The Encyclopedia of Integer Sequences (Academic Press, 1995) to be the product of the first n factorials. So the superfactorial of 4 is
sf(4)=4!*3!*2!*1!=288 and
sf(n)=n!*(n-1)!*(n-2)!..........2!*1!

Alternative definition

Clifford Pickover in his 1995 book Keys to Infinity used a new notation, n$, to define the superfactorial
x$=(x!)^(x!)^(x!)^(x!).....{x! times}

Source:Wikipedia

#423 Re: Euler Avenue » Quadratic Equations » 2016-12-03 22:22:33

David, I recommend you to read every topic on quadratic equations from mathisfun.com. I see you don't know about it. It is very much required in mathematics. Please do it quickly.

#424 Re: Maths Teaching Resources » Maths Books » 2016-12-03 22:05:37

I'm interested in Arithmetic, Geometry, Graphs, Algebra and so on. I do not know much about calculus as you know I'm just in class 8 now.

#425 Maths Teaching Resources » Maths Books » 2016-12-02 23:24:06

iamaditya
Replies: 162

Can anyone suggest me some excellent extremely hard maths exercise books please.

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