Pi Definition and 514 Threads

Hi all, Would it be possible to try to predict Pi by a neural net. So basically when you input 1 into the neural net you will train it to output 3. Next input 2 and train it to ouput 1. Etc... Next after training the net such that it will predict the first 1000 positions correctly would it...

Homework Statement why we can't form the pi group by using repeating variable of (μ, ρ , v) or (D, v , μ ) ? http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/dimension/node9.html http://www.efm.leeds.ac.uk/CIVE/CIVE1400/Section5/dimensional_analysis.htm...

Another interesting article Pi in the sky by the intrepid duo Ali Frolop, and Douglas Scott. Those pesky CMB anomalies again! Garth

Why do we assume that the circulating pi electrons induces another magnetic field, B_in, that adds to the external mag field, B_ext, instead of opposing B_ext? Couldnt the pi electrons just as easily oppose B_ext? This lecture says the protons on benzene will experience greater effectual...

Nerds of the world are celebrating our annual nerd-o-rama, Pi Day. Have a great one.

Question: The frequencies of the first three harmonics of a 300 Hz square wave are 300 Hz, 900 Hz, and 1500 Hz. If the amplitude of the fundamental is 1.00 A, then the amplitudes of the second harmonic is _____ A, and the amplitude of the third harmonic is _____ A. I found the answer to the...

I find this interesting. You can approximate pi/4 with the Gregory and Leibniz series pi /4 = 1/1 - 1/3 + 1/5 - 1/7 + 1/9 ... (1) btw it takes a lot of terms to get a reasonable approximation for pi. The formuli is pi / 4 = [ ( -1 ) ^ ( k + 1 ) ] / ( 2 * k -1)...

Hello, my question is, why does the decay of K⁺ -> π⁺ ν ν-bar require a loop to be allowed. See images below.* -What is it that makes the decay forbidden in figure 1.4 and not forbidden in figure 1.5? -What does being a first order weak decay and a second order weak decay mean? -I suspect...

Homework Statement in the third photo attached , why do we need to raise the whole pi _3 to power of -1/2 ? can we do so ? if we do so , the original pi_3 will be changed , right ? Homework EquationsThe Attempt at a Solution

Homework Statement http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/dimension/node9.html can somoene expalin about step 4 in the first photo attached ? What does it mean by each group has all the repeating variables and non-repeating variable ? Homework...

Use an appropriate volume integral to find an expression for the volume enclosed between a sphere of radius 1 centered on the origin and a circular cone of half-angle alpha with its vertex at the origin. Show that in the limits where alpha = 0 and alpha = pi that your expression gives the...

Pi is everywhere in physics. Why is that.

Is pi = 3.14159... only true in our flat universe? We talk about whether our universe is open or closed - positive or negative curvature - and scientists have concluded that it is very nearly flat. If the universe did indeed have a large positive curvature, would that result in a different...

Dear forum, I have an raspberry pi (which is using linux and bash),and I am trying to make connection with Windows7 and 8. As we know that we just need to download Putty.exe on the windows 7, run and insert IP address on to the box, another window will be showed up and "log in as" and...

Homework Statement So, my teacher said that the biggest phase difference is pi. But what if you have two waves arriving at a point, such that the instruction from one wave is a phase of (7pi/4), and from the other is (3pi/4), then the phase difference is (9pi/8), which is larger than pi. So...

I was lying awake the other night and thinking about Pi and flatlanders. I haven't done a lot of topology reading, so forgive my naivete. Pi on a flat surface is a number we know well, but what happens to the ratio of a circle's diameter to its circumference on curved surfaces? First question...

Hello folks, Can anyone tell me why does a PI controller uses an Anti-Windup circuit?what is the main purpose of using it?

Dear PF Forum, Why in "Contact" film in 1997 if I remember. The frequency for receving signal from aliens is Hydrogen times Pi? I can understand, at least grasp, that the frequency uses Hydrogen frequency, because it's the most simple element. Can't use 92.0 MHz as Sonora Radio in Jakarta...

Homework Statement I'm trying to confirm the speed of an antimuon in the \pi^+ \rightarrow \mu^+ \nu_{\mu} decay through the laws of conservation but it doesn't add up. Homework Equations [/B] 1.Energy-momentum relation: E^2 = (pc)^2 + (mc^2)^2 2. Rest masses: m_{\pi} = 139.6 \...

Hi I was thinking about calculating Pi digits (for example up to 1000) using C programming Unfortunately there seems to be no one in our university to know how (even teachers) I know that i have to use arrays but i don't know how And i don't know what is the best way to do it ? -4 times the...

Haven't seen a thread on this before so I'll start one. The Raspberry Pi 2 is really a marvel. For $30 you get a 90MHz quad-core processor and 1GB RAM on a Linux platform. The platform also comes standard with an ethernet connector, 4 USB ports, HDMI, and a micro SD slot. I picked up my...

I'm an undergraduate involved in a research project. My advisor is a faculty member who has requested that I walk him and our postdoc collaborator through a paper that is relevant to our project; it's a 24-page in-depth journal article. I made an attempt at walking them through a shorter...

Hello everyone, I found in the PDG booklet that pi 0 decay into e+ e- gamma is more likely to happen than to e+ e- only ..is there a reason that favorises the first decay?

Homework Statement A capillary filled with water is placed in a container filled with a chemical of concentration C_{0} , measured in number of molecules per unit volume. The chemical diffuses into the capillary of water according to the following relation (where x is distance along...

Hello, I understand the fact that pi mesons are superpositions of uubar and ddbar. But what happens if a decay only produces a single type of meson? I am not sure of this, but omega baryon decaying into xi-minus and a neutral pion seems to produce ddbar mesons, is it so that only a single type...

Homework Statement So I have a problem with the integral ∫ sin(x)/x^0.1dx from pi to infinity My teacher said this wouldn't require any maths beyond calc 3, but for some reason I cannot come up with a solution. Homework EquationsThe Attempt at a Solution I have attempted a maclaurin series...

I was wondering if someone is very well into the Buckingham Pi Theory and can assist me in understanding the outcome. I have two dimensionless equations and I need to get an understanding on how they were made by the Buckingham Pi theory. The situation is considered for the reynolds number...

Consider the following equation: eiπ = -1 Is π in that equation just a number or do I need to interpret it as radians ? I mean, if I defined a 'diameterian' so that π diameterians would make the full circle, would the above equation still be correct ? Thanks

Prove $\sqrt{2}+\sqrt{3}\gt \pi$.

Dear PF FOrum, I have a question about Pi. In some Youtube videos, they explain why the volume of a sphere is so,... Why the area of a sphere is so,... Why the area of a circle is so,... All are good explanations, with or without differential. But I can't find the proof why Pi is 3.14. I have...

In BJT hybrid pi small signal model, we have a resistor "ro" between Collector and Emitter. This resistor is to include the change in collector current when there is a small signal voltage change between collector and emitter. (due to early effect) I am finding that all BJT hybrid small...

If pi is a part of the area of a perfect circle, which I assume we can construct. Why does it have uncertainty? Can we just measure the area of circle and assign a perfect value for pi. If the answer is our measurements are limited to the instruments that we use, is it not the same for other...

Is this equation of any use or in any way interesting? c = speed of light (m/s) e = euler's number I don't know much about physics but 2^6=log_2(64), this is a binary logarithm so would this mean that computers, the world (c and e) and circles(pi) all be related somehow by this equation?

Homework Statement In buckingham pi theorem, you have p=n-k dimensionless groups (π1, π2,...) where n=number of total variables and k=number of total units among the variables For example, let's say we want to relate: ρ~m/L3 (density) μ~m/L*t (viscosity) v~L/t (velocity) d~L (distance) Da~L2/t...

hello there, how to tune PI, PD and PID controller according to rule of thumb?

So I have looked over a few other posts and do not feel like they are covering what I would like done. So I am currently using an Arduino Uno for the controller and am wanting to use an onboard Raspberry Pi in order to run the code and will be attached to my schools wifi in order to have a...

Hello, I've written a program that executes the following control diagram. Now I am trying to calculate the PI controller gains such that I can achieve a settling time of 0.06s and a damping factor of 1. How can I do this? I tried sketching a control diagram of the relevant portions...

Homework Statement In a course I am studying, I have been asked to calculate the distributed parameters of a line whose Pi model has been provided. I simply quote the question here for clarity of my question: Homework Equations C = \frac{{2\pi \varepsilon }}{{\ln \frac{b}{a}}} R =...

One million digits of pi, printed out on a mile long piece of paper. What do you think?

Homework Statement From an old edition of the Anton calculus text, I am asked to prove cos-1(-x) + cos-1(x) = π or equivalently cos-1(-x) = π - cos-1(x) Homework EquationsThe Attempt at a Solution Earlier I proved that sin-1(x) was odd by noting sin-1(sin(x)) = -sin-1(sin(-x)), so I...

It has been eons since I've done any trigonometry, but I just can't prove how this following relationship holds for $n = 4, 8, 16, 32, \dots$ The relation is: $$ 2 \biggl( \! \frac{A_{2n}}{n} \! \biggr)^2 = \, 1 - \Biggl( \sqrt{1 - \frac{2A_n^{\phantom{X}}}{n}} \, \Biggr)^{\!2} $$ I've subbed...

The ratio of the circumference of a circle to the radius is Pi. Our value of Pi is an irrational number and is calculated assuming a flat curvature of space-time. But our universe as a whole, while very flat, probably has some small amount of curvature -- in addition to the greater local...

I created this animation to celebrate Pi Day yesterday and thought Id share it with you guys :) BENBOBBY.

On 3.14.15 at 9:26:53 3.141592653 Set your alarms!

I have a cosine calculator problem, and it keeps coming up wrong. So I figured to test it would be to do cosine of -1 which should be pi, either symbolically or numerically but it doesn't come out with either. It either produces cos(1) or .540302. It used to give pi as the symbol or as the...

variable pi formula Diameter (mm) = 0.0000003 : (pi of D - 3.1416 )^2 Pi of D is variable from 3.1416 to 3.1589...

Well I'm super confused about this cause the trust is balanced. here's my question:which is right:3.14159265359 blah blah blah -supported by google -supported by http://www.quora.com/Why-is-PI-22-7 also says that 22/7 is an approximation or 22/7...

Homework Statement a) A orifice, diameter d (m), in the walls of a tank discharges water under a head, h (m), subjected to gravitational acceleration, g (m/s2). If the fluid has density, ρ (kg/m3)and viscosity, μ (Ns/m2), show that the quantity of fluid Q (m3/s) flowing out of the tank may...

Hi everybody, I have implemented PI control of a DC motor and it works properly at high speeds (50rad/s) but if I lower the reference speed to 5 rad/s, there are fluctuations in its motion. Initially, I thought it could be due to the limitation of my current sensor (LTS 6 np) but I added some...