Variable Definition and 1000 Threads

Homework Statement Water with mass density ρ are being shoot from a jet with cross sectional area A and velocity v0 at a man with mass m0. 1. Find the force acting on a man at rest (assume all the water are absorbed in the clothes) 2. Find the force acting on a man escaping at velocity v<v0...

F(y)=Integral(e^{-x^{2}y^{2}}dx between y and 0 (where y>0). I know you have to make substitutions with y, but then you have to make a further substitution along the way and that's where I'm a little lost. Can anyone help point me in the right direction? I know you can set u=-y^{2} and v=y in...

Ok, this one's got me stumped! Let's take as an example the probability density function for a random variable X so that: f(x) = \frac{4}{3x^{3}} 1≤x<2 f(x) = \frac{x}{12} 2≤x≤4 f(x) = 0 So the CDF for this variable comes out as: F(x) = \frac{-2}{3x^{2}} 1≤x<2 F(x) =...

I made an epidemics SIR model but want to vary one of the parameters but it's not working can someone help I pasted the code below I believe the parameter I want to change, v, is not updating: v_range=linspace(0,.1,1000); numinfected=0*v_range; for vi=1:1000; for klok=1:100000...

Homework Statement An object is moved from 0 to 9 meters with a force varying according to the function F(x)= 50(5-square root x). What is the work done. Homework Equations The Attempt at a Solution I tried to take the integral and evaluate it from 0 to 9. I get 1350J no...

Homework Statement For every (x,y) in Z^2 solve : 6x-5y=1The Attempt at a Solution I did 6x=5y+1 and then i said let x=5n+1 so then we get 6(5n+1)=5y+1 and that gives that y=6n+1 so the solution is (5n+1,6n+1). Is this the correct way of solving this?

Homework Statement In the winter, the monthly demand in tonnes, for solid fuel from a coal merchant may be modeled by the continuous random variable X with probability density function given by: f(x)=\frac{x}{30} 0≤x<6 f(x)=\frac{(12-x)^{2}}{180} 6≤x≤12 f(x)=0 otherwise (a)...

Homework Statement Hello everyone. I have differential system consists of: \frac{dx_1}{dt}=x_1(1-2x_1+x_2) \frac{dx_2}{dt}=3*x_2(x_1-x_2) I want to change variable using: x_i=a_iz_i i=1,2 where z is a unit vector and rewrite the differential equations Homework Equations...

what I've posted is a question from a study guide for our test next week, on the attachment is my work. The professor only did SISO examples in class and moved really fast, I am not really sure if i found state equations correctly using KVL and KCL. Any help is appreciated

Suppose that X is a random variable distributed in the interval [a;b] with pdf f(x) and cdf F(x). Clearly, F(b)=1. I only observe X for values that are bigger than y. I know that E(X|X>y)=\frac{\int_y^b xf(x)dx}{1-F(y)}. Moreover, \frac{∂E(X|X>y)}{∂y}=\frac{f(y)}{1-F(y)}[E(X|X>y)-y] I...

Hi all! I have a question about fortran. So far in my coding, if i wanted to define a function ( say f(x) ) I would manually set a grid for x, and then define f for each x value, so that i would have a vector for f and a vector for x. However, I'd now like to use the 'function' command, so i can...

Hey guys ^^, basically there's this problem I've come across and I am somewhat curious of your opinions on it. There's a bike that was previously on an incline that begins to run on a level surface. Assuming that the only resistive forces acting on the bike are due to aerodynamic drag I want...

My answer for part (i) matches up with that of the book but solving for part (ii) has gone awry. Can anyone help me clear this up? Many thanks. Homework Statement Q. The given diagram (see attachment) shows part of the graph of y = x2. p(x,y) is a point on the curve & a(6,0). bp \perp...

Why would I see a fairly significant difference in r-square (98.5% vs 85%) when I change my dependent variable from Total $'s to $'s per lb? My independent variable in both cases is weight. Each equation yields essentially the same answer in all tests of weight (within .08%). How do I know...

#include <iostream> using namespace std; int a; int main() { cin >> a; int c [a]; for (int i = 1;i!=a+1;i++) { c [i] = i; } for (int i = 1;i!=a+1;i++) { cout << c [i] << endl; } return 0; } This compiles and does exactly what it's supposed to. But wait...

For a senior engineering class I need to design a device that, using a 5 volt source I need to deliver a 5mA current with a load that can vary from 500-100K ohms. Using transistors I know one can create a current limiting circuit, but once the resistance gets high enough (not sure how to...

Given a character variable character*10 name write (6,111) name 111 format (?) what do I put in the format statement to print the hexadecimal contents of name?

Edit: I have to think more about this, I'll post later.

Hey, Every where I look I can only find books and pdf talking about the uniqueness and linear independence of the solutions but I haven't been able to find a procedure of finding the solutions to one of these ode's if you haven't been already given a particular solution. I've been trying...

Homework Statement if a 10-N force is used to compress a spring with a spring constant of 4.0x10^2N/m, what is the resulting spring compression? Homework Equations The Attempt at a Solution

I am trying to factor the following equation $$\large(x^{\frac{1}{n}}+a)^{n-1}$$ but the fact that the exponent is n-1 is throwing me off. How could I go about factoring out this equation? Thanks.

Homework Statement The question says ti find the derivative of y with respect to the independent variable. The equation is: y=4 ln 2t. Homework Equations I know how to find derivatives using the product/quotient/chain/etc rules, but that isn't what the question is asking for. I...

Homework Statement A multi-plate variable capacitor has 4 pairs of plates. The plates, when closed, are separated in air by 0.01mm. A capacitance range of 10 - 400 pF is required a) estimate the required radius, R of each plate. b) The capacitor is set to the maximum of 400 pF and is...

Say we have one spin-less electron in a box in the ground state. Say we have dials on the outside of the box that can vary mass and charge of the spin-less electron. Suppose we start with one spin-less electron in a box with m and e set to as near zero as we please, but not zero. As m and e go...

"Show that if a>b>c>0, then the function $f(x,y,z) = (ax^{2} + by^{2} + cz^{2})e^{-x^{2}-y^{2}-z^{2}}$ has two local maxima, one local minima, and four saddle points"

With the number i, its possible to create a wave function with just one variable. example: f(x)=i^x or.. f(x)=2^ix But is there any wave function without the number i AND with only one(x and y) variable? can this be created?

Homework Statement A variable resistor, R, is connected to the terminals of a battery (dashed box in the diagram). The graph below shows data collected in the circuit as R is varied. What is V0, in volts? What is the internal resistance, r, in ohms? Homework Equations Ohm's Law The...

Hello, I've been staring at this question for an hour with no luck.. if anyone could point me in the right direction that would greatly appreciated! Homework Statement a = acceleration v = velocity x = displacement m and n are constants vt = terminal velocity Show that after...

Homework Statement A one-dimensional force acts on a particle of mass m = 6.26 kg in such a way that its position is given by: x = 0.484t^3 - 33.6t Find W, the work done by this force during the first 1.49 s. Homework Equations W=F*s W=mgs Integration The Attempt at a...

I can't seem to find this anywhere. What's d/dn(∫ n(w) dw)? That's the derivative wrt n of the integral of n over w (note: n is a function of w). Seems straightforward enough. Is there a simplification? Thanks

Homework Statement The force on a particle is directed along an x-axis and is given by F = F0(x/x0 - 1). Find the work done by the force in moving the particle from x = 0 to x = 2x0 Homework Equations The Attempt at a Solution It looks like the force is a recurrence relation or...

1. Homework Statement During a typical Pennsylvania winter, I80 averages 1.6 potholes per 10 miles. A certain county is responsible for repairing potholes in a 30 mile stretch of the interstate. Let X denote the number of potholes the county will have to repair at the end of next winter. 1...

I know the E[X] = Integral between [-inf,inf] of X*f(x) dx Where X is normally distributed and f(x) is the PDF How do I find the expectation of X4? Bare with me because I'm useless in Latex So far what I've done is written the integral as Integral between [-inf,inf] of X4*f(x) dx...

Homework Statement I wanted to solve a ode which has Brownian motion as a variable coefficient Homework Equations 2x2y'' + y' -ρy = 0 where x is the Brownian motion with respect to time ρ is a constant The Attempt at a Solution I have tried power series with no solution. Is there a...

Homework Statement Im trying to model this in simulink. I am having a little trouble getting things to work. I need to create a variable delay model or basically implement a "flanger" effect. Flange A flange is an audio effect, which is achieved by combining two identical signals with...

So, I want to use cin >> to get a user input that must only be int. How can I check the type of the input? Thanks.

Separable equations: How do you know which variable to solve for? + extra question Homework Statement I attached a sample problem with variables u and t. How do I know what the answer should be at the end? In terms of u or in terms of t or it doesn't matter? Homework Statement I also...

Homework Statement Find the Mean and Variance of Random Variable Z = (5x+3) Using data set:Using: & The Attempt at a Solution

So I don't understand why if you have something like U(x,y) = f(y+2x) and you take \frac{\partial U}{\partial x} = \frac{\partial f}{\partial x} you get \frac{df}{d(y+2x)} * \frac{d(y+2x)}{dx} Why does the partial derivative just change to the total derivative for one variable? It...

what does it mean "variable Direct Current"? I am confused on the point where i see the word variable DC in a question(see attachment). If a DC vary like a curve then in some cases it can be like AC. How is it varying (Don't tell me answers.)

Say we have a laterally insulated beam and some boundary conditions at either end, be it convective or fixed-temperature, but the cross-sectional area is variable. If the cross-section were constant I'd just say it were a 1-D problem, but I'd imagine that having the cross-sectional area be a...

Homework Statement Here is the problem: A variable capacitor has seven armatures in the shape of half-circles with a radius of 2 cm. The armatures have a distance of 1 mm separating them. Find the capacity when the angle θ is: (a) 0 degrees; (b) 45 degrees; (c) 135 degrees. Homework...

http://bildr.no/view/1115383 i wonder if anyone could explain the proof for theorem 4.3 i have understood definition 4.3

New here, sorry if I'm in the wrong place or unclear, etc. I've been looking at torsion on solid plates and the torsion constant. I was wondering how to handle the torsion constant on a plate of changing cross section (e.g. there are holes drilled in it, changing the area of the cross section...

I have a shooter that shoots a ball at a fixed angle of 65 degrees from horizontal. The shooter is aimed at 3 targets of different but fixed heights. The top target is at 1.536 meters above the shooter, the middle target is at 0.571 meters, and the bottom target is -0.318 below the shooters...

Dears, If a random variable is generated with the pdf of p(f) = 1/(f^x), how can I derive the upper bound or lower bound of the random variable? Thanks,

Dears, If a random variable is generated with the pdf of p(f) = 1/(f^x), how can I derive the upper bound or lower bound of the random variable? Thanks,

Hi, I am writing a Matlab function(script), which take some input. I have several datasets in the workspace, say dataset1,dataset2,dataset3, ect In my function, I have tried to use data = input('Please input your dataset', 's') and then use 'data' as a variable for some computation, say...

Homework Statement if z=x+iy and sqrt(z) = u+iv u=±(1/√2)*√(x+√(x^2+y^2 )) v=±(1/√2)*√(-x+√(x^2+y^2 )) How must the signs on these result be chosen? 2. The attempt at a solution I wondered if it was something to do with ensuring √(z) was always positive, but then ruled this out as...

Hi, Homework Statement lim (xy²)/(sin(x² + y²)) (x,y) -> (0,0) The Attempt at a Solution I think the answer is 0, but I don't know how to get rid of the sin (x² + y²). I thought about using taylor series but I'm not sure if that works with two variables. Can someone help me out?