Normal Definition and 1000 Threads

Let X be standard normal and Y uniform [0,1] find the distribution of Z=X/Y. i think i managed to deal with this problem up to the integral stage: P(X/Y< t ) = P(X<Y*t ) thought of : 1. F_{z}(t) = \int^{1}_{0}\int^{yt}_{0}f(x,y)dxdy 2. F_{z}(t) = \int^{yt}_{0}f(x)dx maybe is neither one of...

Hey guys, i'm building an apparatus with a sliding pin containing a spring and a ball. I want to lock in two different positions so I've rounded two slots in the housings. I would like to know what is the equation two find the normal force of the spring on the ball depending on the displacement...

Homework Statement r(t)=cos(t)i+sin(t)j+sin(2t)k Find the curvature κ, the unit tangent vector T, the principal normal vector N and the binormal vector B at t=0. Find the tangential and normal components of the acceleration at t=∏/4 Homework Equations T(t)=r'(t)/|r'(t)| N(t)=T'(t)/|T't|...

Proposition: If every element of G/H has finite order, and every element of H has finite order, then every element of G has finite order. Proof: Let G be a group with normal subgroup H. Suppose that every element of G/H has finite order and that every element of H has finite order. We wish to...

Ignoring the fact that it is redundant at times, is this proof correct? Also, is there a way to show that same result using the fact that K is closed with respect to conjugates rather than the fact that for all a in G, aK=Ka. Thank you! :) Proposition: If H and K are subgroups of G...

why is hydrogen the only element in the periodic table that lacks a neutron?

cylinder of mass m and radius r rests on two supports of same height. one is fixed other slides with velocity v.determine normal force N by the cylinder on stationary support at the moment when distance between the point of contacts A and B of cylinder and support) is r√2assuming supports were...

Homework Statement The line that is normal to the curve x2+2xy-3y2=0 at (5,5) intersects the curve at what other point? 2. The attempt at a solution I differentiated the equation, found the slope of the curve at that point, and I then found the equations for the tangent line and normal...

I've been reading that the diagonalizable matrices are normal, that is, they commute with their adjoint: ##M^*M=MM^*##, where ##M^*## is the conjugate transpose of ##M##. So a matrix is diagonalizable if and only if it is normal, see: http://en.wikipedia.org/wiki/Normal_matrix But from...

Suppose you have a single variable differentiable function r: R -> R restricted to an interval, like [0,1] for simplicity, if you want. Consider the surface of revolution obtained by rotating the graph of r around the x axis. How do I find the NORMAL VECTOR to the surface at each of its points...

I took a LA course in the spring, and was interested by the least squares method for building models. I decided to practice this concept by attempting to build a model that would predict ticket sales for the Mega Millions lottery given the jackpot amount. I have 249 data pairs of jackpot and...

I want to calculate \int_a^b \frac{1}{\sqrt{2 \pi \sigma^2}} e^{(-(x-\mu)/\sigma^2)} log_2 (1 + e^{-x}) dx

I've been interested in this function Youtube offers on videos ever since I first used it a few months ago. It's amazing. Some videos are just way too long. The speakers will have something very informative to say, but they'll just ramble and/or speak very slowly. For some reason, Youtube only...

This is the my homework.Who can solve this for me ? i upload my solutions and the problem .Thanks.

Hi guys ^^ I am still at A level physics, so don't flame me for my lack of knowledge Now i have been taught that for ex: We have a block of wood named A at rest on a perfectly smooth surface. If we analyse a free body diagram, we have a weight mg downwards acting on the block and a normal...

Given a bivariate gaussian distribution, I'm attempting to find the probability p for which the ellipse of all points (x,y) for which P(X = x, Y= y) = p contains a given % of the samples drawn from the distribution. I want the 2d equivalent for the 1 dimensional case: given a normal...

1) If X~N(μ,σ2, find the value of c in terms of σ such that P(μ-c ≤ X ≤ μ + c) = 0.95 Attempt: Ok so I have a feeling I will eventually need to reference a standard normal table, but I tried to standardize the rv first: P (-1 ≤ (X-μ)/c ≤ 1 ) = 0.95 Now here's where I'm stuck, what...

Homework Statement Hi I am having tough time figuring out how to determine normal stresses σx, σy, σz using the flexure formula. All that confuses me is which moment to take for which σ. My for σx or Mz for σx and so on.. I will post an example question. In the question below, find the...

Homework Statement Let Z follow a standard normal distribution. Compute E(Z^3) and E(Z^4) Homework Equations I know that mu is 0 and sigma is 1. And f(z) = e^(-z^2/2)/sqrt(2pi) The Attempt at a Solution I tried to take the integral of ∫Z^3 * f(z) from the integral from -∞ to ∞...

I'm having trouble finding the equation normal to the plane for part (ii). The vector equation I got for part (i) is r=(1/2,1,2/3) + t(3/2,2,-2/3). How do you deduce the normal vector from this? The answer is the vector (9,12,-4). I've tried anything but don't know where they got this result...

Stokes' theorem uses the curl of a vector field dotted by the normal vector of a surface...but what happens when you use a larger or smaller normal vector? You get a different answer but the theorem doesn't specify to use the unit normal vector. So which normal is the correct one to use...

Homework Statement If A,B and C are normal subgroups of G where B\subseteqA show that A\bigcapBC=B(A\bigcapC) Homework Equations The Attempt at a Solution Let x\inA\bigcapBC.then x\inA and x\inBC Now as B\subseteqA thus BA=A.thus left side is BA\bigcapBC Dont know how to proceed.

Hi - I have a quick question. I understand that the sum of two normal distributions is a normal distribution. Now let's say I have the z-score from one normal distribution and the z-score of another set of data that is also normally distributed and a third and a fourth etc. I just want...

Hi, I have a dataset of a random variable whose probability density function can be fitted/modelled as a sum of N probability density functions of normal distributions: F_X(x) = p(\mu_1,\sigma_1^2)+p(\mu_2,\sigma_2^2)+\ldots+p({\mu}_x,\sigma_x^2) I am interested in a fitting method can...

Show that if X is a normally distributed random variable with parameters mu and σ2, then then show that for each real number x we have: фX(x)=ф[(x-m)/σ] I have really hard time. Any possible hint is greatly appreciated.

Quick question on bivariate normal distribution please: I know for a bivariate normal distribution, the two variables are marginally normal and all the conditional distributions are also normal. Is the reverse true? i.e. if you have two random variables that are marginally normal...

Homework Statement Given in uploaded file Homework Equations σallow=\frac{P}{A} τallow=\frac{V}{A} The Attempt at a Solution Given in uploaded file Answers are d=16mm, h=10mm I tried using methods used in previous questions but it didn't work out for me here, if anyone could...

I'm on the last chapter of a 1200 page calc book, I'm really psyched. Homework Statement The Attempt at a Solution The method I learned for finding the unit normal of a vector field, n, is take the derivative of the equation and divide that by the magnitude of the...

Am I right? Thank you!Problem: A cereal brand of cereal claims that the mean number of raisins in each box is 80 with a standard deviation of 6. If the raisins are normally distributed, what are the chances that an arbitrary box has 1) fewer than 70 raisins and 2) more than 90 raisins. What...

Two buckets of nails are hung one above the other and are pulled up to a roof by a rope. Each bucket has a mass of 5.0kg. The tension in the rope connecting the buckets is 60 N. Calculate the acceleration of the buckets. So here's what I did: mt= ma + mb (m which is equal to mass) mt=...

good day! i need to prove that the alternating group An is a normal subgroup of symmetric group, Sn, and i just want to know if my proving is correct. we know that normal subgroup is subgroup where the right and left cosets coincides. but i got this equivalent definition of normal group from...

I have a list of bearings that I want to convert. The normal degrees circle is oriented with 0 to 360 going counter clockwise. I have degrees calculations that require this. I have a set of data from bearings from an aircraft where I need to convert those bearings to normal degrees bearings. As...

Homework Statement Vector field ##\vec F= 4x \hat i+4y \hat j +3 \hat k## Let S be the open surface above the xy-plane defined by ##z=4-x^2-y^2## a. Evaluate normal outward flux of F through S. b. Use Stokes' theorem to evaluate the normal outward flux of ##∇ \times \vec F## through S. c...

Every semester, whenever I begin to learn a new subject, that is, a more advanced class of the previous subject (i.e. algebra -> pre-calc -> calc -> diff eq, etc.) I forget a lot of the stuff I learned in the previous class when I'm learning the new content and constantly have to review all the...

Given the function: w=\sqrt[3]{(z-5)(z+5)} which is fully-ramified at both the finite singular points and at infinity, how does one create the normal Riemann surface for this function? It's a torus but I do not understand how to map a triple covering onto the torus so that it's fully-ramifed...

H=A3= {(1),(1 2 3),(1 3 2)} and G=S3 ={ (1),(1 2 3),(1 3 2),(1 2 ),(1 3),(1 2 3) } Is H is normal subgroup of G ? I try g=(1 2 3 ) for gH=Hg but gH≠Hg for all g ε G.In this situation,H is normal subgroup pf G?

Let r and a each be a position vector of a point on a plane. Let n be the normal to the plane. The normal equation of the plane would be: n.(r-a) = 0 r.n = a.n My question is, the equation doesn't really 'describe' a plane...so what's the purpose?

I have to compare measurements in a normal distribution with a theoretical gauss curve on "probability paper" (the y-axis has percent). Does anyone know any online guide/ information? thanks, have wasted the last three hours on this

According to the Snell's Law refractive index n21= sin i/sin r, but when we use this equation while having a incident light normal to the surface of lens or any other refracting surface it becomes 0/0. So how can we define Snell's law in this situation?

We're given x^2+2*y^2=1. so x^2=1-2y^2 now using distance formula d^2=x^2+y^2 since x^2=1-2y^2, substituting it in the distance formula we get: d^2=1-2y^2+y^2=1-y^2; differentiating and then setting the eq to 0 we get; 0=-4y or y=0. now x^2=1-2y^2=1 so x=+-1 so point having...

1. A 5 kg board is arranged between 2 sawhorses (at right). If the board is in static equilibrium, what is the normal force on the board from sawhorse 2. Link for the picture the question is referring to. h.ttp://i.imgur.com/nBC6A.jpg a. F2,normal = 0 N b. F2,normal = 49.0 N c...

Homework Statement Consider a 2D spacetime where space is a circle of radius R and time has the usual description as a line. Thus spacetime can be pictured as a cylinder of radius R with time running vertically. Take the metric of this spacetime to be ds^{2}=-dt^{2}+R^{2}d\phi^{2} in the...

Homework Statement Consider z = -3x - y + 11 Find a unit vector perpendicular to the plane, and find a vector parallel to the plane. Homework Equations The Attempt at a Solution 1.) 0 = -3x - y + 11 - z -11 = - 3x - y - z Perpendicular vector is then: -3i -j -k...

I bought a ravpower brand laptop power adapter half year ago,it works well before,but this week i find it will become very hot,I don't know why.But I am thinking maybe it is relative with the time of using or the voltage?Or some other problem?Sometimes I play games for all day and I have a bad...

Homework Statement Consider the subset H = {0,3} of the group Z6. (i) Prove that H is a normal subgroup of Z6. (ii) Prove that Z6/H is isomorphic to Z3. (Give an explicit isomorphism) Homework Equations In order to be a subgroup H must be closed under +6, have an identity, and have an...

Hi all, just a small question: why does a normal metal junction does not show a josephson like current when inserted in a squid setup? I guess it is something related to the coherence of the ground state...

Hi, why does the energy of the system equals the sum of the energy of the modes? The book I'm reading only states it, it doesn't prove it.

Hi, Can someone here help me understand how to illustrate maps of analytically-continuous paths over algebraic functions onto their normal Riemann surfaces? For example, consider w=\sqrt{(z-5)(z+5)} and it's normal Riemann surfaces which is a double covering of the complex plane onto a single...

Homework Statement An infinite cylinder with radius 1 is aligned with axis Y, A point light source with intensity 1 is located at (2,2,10) An observer is located at (3,1,4). He is looking in the direction of the origin of the coordinate system. What are the coordinates of the point on the...

Homework Statement Homework Equations σ=P/A σ=My/I τ=VQ/ItThe Attempt at a Solution I'm on part C, pretty sure I have A and B, so I'm using a W18x46 Beam. I have drawn shear and moment diagrams. I just want to be clear on what part C is asking... I'm assuming this point is at the end of...