Polar Definition and 1000 Threads

The question is: "In polar coordinates, what is the impedance of a circuit that has an admittance of 7.09 millisiemens at 45 degrees?" The official answer is: "141 ohms at an angle of -45 degrees". I don't understand this. 7.09 millisiemens is 141 ohms, and the positive phase angle...

Hi all I'm trying to find out how to draw a curve in polar coordinates. Can anyone help me with a book or something and help me find out how to draw curves in polar coordinates?

Homework Statement Polar plot the following sin[t] U cos[t] sin[2t] U cos[2t] sin[3t] U cos[3t] sin[4t] U cos[4t] sin[5t] U cos[5t] Notice that cos[t] and sin[t] are the same graph rotated 90 degrees only? Interesting! Just like the cartesian graph. Now here is something more...

Homework Statement Hey I have to create a six-pointed star and a hexagon with polar coordinates using MATLAB. I don't need help with using MATLAB, I just need help with the math. Note that I don't really need to know how the math sense this assignment is for a CSE course. I just don't...

Hello, I'am new here and happy to find this great forum! Here's my first question: there's an explicit function as follows: y=2.sin(x)-1 The transformation to polar form (r=3cos(\theta)) - x=r.cos(\theta) - y=r.sin(\theta) So I get: r.sin(\theta)=2.sin(r.cos(\theta))-1 Now you see...

Homework Statement Consider a velocity field where the radial and tangenetial components of velocity are V_r=0 and V_theta=cr, respectively, where c is a constant. Obtain the equations of the streamlines. Homework Equations x=rcos(theta) y=rsin(theta) The Attempt at a Solution I...

I have solved part a, I just have no idea how to go about doing part b. If anybody could point me in the right direction, that would be greatly appreciated! Homework Statement a. Express z = \frac{1 + \sqrt{3}i}{-2 -2i} in the form rcis\theta b. What is the smallest positive integer n...

Question: Given (-2*sqrt3) – ( 2*i) = 4*e^(i*7*pi/6) Perform the following: (a) Convention I: angle go from (0) to 2*pi. (b) Convention II: angle goes from (-)*pi to (+)*pi. = = = = = = = = = = = = = = = = = = = = = = = = = = = Part (a): Convention I: angle go from (0) to...

Hello All, I'm reviewing some notes for a course and am confused by one step that they do. They are deriving an equation for the ampiltude of a wave that is being damped and driven by a force. I understand it all except for one step in which they state that: (\omega_{o}^{2} - \omega^{2}) -...

Homework Statement Determine the polar moment of inertia and the polar radius of gyration of the shaded area shown with respect to point P. http://imgur.com/8Kc1S Homework Equations Jp = Ix + Iy Ix = &int y^2dA Iy = &int X^2dA The Attempt at a Solution A = 2(a/2)(a) +...

I don't remember ANYTHING from this section when I took Trig but we're finding the area of curves in the polar coords. Looking at the book they give us this equation r=2cos3\theta I can see, and I know how to figure out its a 3 leaf "rose" symmetrical about the theta= zero axis, but I can't...

Homework Statement I am doing even problems in my book to study and i want to check this answer to see if it is right. q: Find the area enclosed by one leaf of the three-leaved rose r=sin3(theta) Homework Equations A= integral 1/2 r2 d(theta) The Attempt at a Solution i used the...

Homework Statement Mass m whirls on a frictionless table, held to circular motion by a string which passes through a hole in the table. The string is slowly pulled through the hole so that the radius of the circle changes from l1 to l2. Show that the work done in pulling the string equals...

Homework Statement Transform to polar coordinates and evaluate... \int^{a/\sqrt{2}}_{0} dx\int^{\sqrt{a^2-x^2}}_{x}\sqrt{x^2 + y^2}dy Homework Equations x^2 + y^2 = r^2 x = r cos \theta y = r sin \theta I've been struggling to make sense of this problem, it should be easy, I'm...

Homework Statement Evaluate the following triple integral by switching it to spherical coordinates? The integrand is r dzdrdθ The limits for the inner integral are 0 to r The limits for the middle integral are 0 to 3 The limits for the outer integral are 0 to 2π Homework Equations...

Homework Statement Using this polar equation: r = \theta + sin(2\theta) Find the angle \theta that relates to the point on the curve when x = -2 I'm not sure where to start...but my guess is to convert the equation to another form...any help is appreciated.

Homework Statement integrate 1/((1+x^2+y^2)^2) dx dy Both x and y going from 0 to infinity Homework Equations x^2+y^2 =r The Attempt at a Solution After that I get 1/(1+r^2) ^2 Cannot visualize the function, do not know what the limits are. If I could have any help it...

Homework Statement r = \theta + sin(2\theta) for 0 \le \theta \le \pi a. Find the area bounded by the curve and the x-axis b. Find the angle \theta that corresponds to the point on the curve with x-coordinate -2 c. For \frac{\pi}{3} < \theta <\frac{2\pi}{3} ...

Homework Statement Where the region is: D = {(x,y)| 0\leqx\leq2;0\leqy\leq\sqrt{}2x-x^2} Double integral over region D with f(x,y) = \sqrt{}x^2+y^2 and respect to dA Homework Equations Trig. Identities: x = rcos(theta) y = rsin(theta) x^2+y^2 = r^2The Attempt at a Solution First, I graphed...

Homework Statement Find the area enclosed by the curves: r=\sqrt(3)cos(\theta) and r=sin(\theta) Homework Equations The area between two polar curves is given by: A=(1/2)\int{R^2 - r^2dr} where R is the larger function and r is the smaller function over an interval. The Attempt at a...

Homework Statement Question requires assumption that the Earth is spherical, all the ice is located at the axis of rotation. Basically if all the ice was to melt uniformally over the surface of the earth, what would be the change in the length of the day? Mass of ice: m= 2.3*10^19 kg Mass of...

Homework Statement Or any coordinates really. In the normal Cartesian plane, the center of mass is defined from the x, y , and z distance as follows \bar{x} = \frac{1}{Area(R)}\iint_R x dA \bar{y} = \frac{1}{Area(R)}\iint_R y dA \bar{z} = \frac{1}{Area(R)}\iint_R z dA Now is there one for...

I need to convert the Laplacian in two dimensions to polar coordinates. \nabla^2 u=\frac{\partial^2 u}{\partial x^2}+\frac{\partial^2 u}{\partial y^2} I am having problems with computing the second derivatives using the chain rule. For example, the first derivative with respect to x...

Homework Statement Find the area of the region inside the lemniscate r^2 = 2sin(2\theta) and outside the circle r = 1 It sucks because I wish I could post a graph, but the graph on my calculator looks like a circle around the origin with radius 1, with an infinity symbol going diagonally...

Homework Statement Sketch a graph of the polar curve whose points satisfy the following: As theta increases from 0 to pi/2, r decreases from 4 to 2. As theta increases from pi/2 to pi, r decreases from 2 to 0. As theta increases from pi to 3pi/2, r decreases from 0 to -1. As theta increases...

Homework Statement http://i1115.photobucket.com/albums/k554/shirozack/polarchange.jpg The Attempt at a Solution why is the limits for the polar angle pi/3 to pi/2? shouldn't it be pi/2 to pi/3? because x goes from 0 to 1/2, since x =rcos(T) 0 = cos(T) , T = pi/2 1/2 =...

i have no idea how to use the functions on here to ill try my best. \int(upper bound a lower bound 0)\int(upper bound 0 lower bound -sqrt(a2-y2) of the function x2y.dxdy firstly trying to map it out... i think its the quarter circle in the top left quadrant with boundaries 0 to a along...

Homework Statement Convert the two equations x=x(t) and y=y(t) to a polar equation of the form r=r(\theta) Homework Equations x=r*cos(\theta) y=r*sin(\theta) r^{2}=x^{2}+y^2 The Attempt at a Solution Perhaps I'm over-thinking this, but in order to eliminate the parameter t, I...

I've been solving some dynamical systems and have had to convert some of the ode's to polar co-ordinates, I've been using the formula r\dot{r} =x\dot{x} y\dot{y} to easily solve for \dot{r} I'm just wondering if there's an easy to use formula to find \dot{\theta} I've been trying...

I've been given a function U(x,y) where f(z) = U(x,y) + iV(x,y) and asked to check if it is harmonic and then work out what V(x,y) is U(x,y) = \frac{y}{(1 - x)^{2} + y^{2}} To check if it is harmonic I can see if d2U/dx2 + d2U/dy2 = 0 I've tried differentiating and it's fairly arduous, so...

Hello, I actually have an exam coming on series, sequences, polar coordinates and parametric equations. The only major thing I'm having problems with is finding area with polar coordinates. Especially when it comes to finding the "area under both curves" for example:"Find the area under both...

I just want to see if my logic is sound here. If we have the paraboloid z=x2+y2 from z=0 to z=1, and I wanted a parametric form of that I think this should work for polar coordinates: \vec{r}(u,v)=(vcosu,vsinu,v^{2}) u:[0..2\pi],v:[0..1] Does this make sense?

Homework Statement 1. Consider the graph of a function defined parametrically by x = g(t) and y = h(t). The slope of the curve at point (g(t), h(t)) is given by h′(t) g′(t) . Use this result and the standard parametrization of a polar curve r = f(delta) given above to show that the slope...

Homework Statement Using polar coordinates, evaluate the integral which gives the area which lies in the first quadrant between the circles x2 + y2 = 256 and x2 - 16x + y2 = 0. Homework Equations The Attempt at a Solution Finding the intervals of integration for the polar coordinates. From the...

Homework Statement x=2acos(theta- pi/3)cos(theta) y=2acos(theta- pi/3)sin(theta) Write everything in terms of x and y Homework Equations cos(a-b)=cos(a)cos(b)+sin(a)sin(b) sina/cosa=tana etc... The Attempt at a Solution I've tried a lot of rearranging, can't figure it out.

RIP Knut. :cry: continued... http://news.yahoo.com/s/yblog_thelookout/20110321/us_yblog_thelookout/world-mourns-loveable-polar-bear-knut

Homework Statement Hi, my teacher gave me this homework assignment and I'm having trouble graphing this one graph. I don't understand her notes that well and am having trouble getting the equation for this graph. See attached for the graph. The graph is a inner loop that is turned...

Homework Statement Fine the area of the region inside the polar curve r=4sin(theta) and outside the polar curve r=2. Homework Equations area under polar curve = 1/2 integral (a,b) r^2 d\Theta The Attempt at a Solution I set up the integral like follows: integral (0,pi/2)...

Homework Statement I don't understand why when we derive the velocity equation of motion in polar coordinates we start with position equal to R times R hat and not (theta times theta hat + R times R hat). Homework Equations none really.. The Attempt at a Solution Is there an assumption I'm...

Homework Statement A particle starts at (d, 0) in polar coordinates and has a velocity of \vec{v}=(u \sin{\theta} - v)\hat{r} + u \cos{\theta} \hat{\theta} where v > u Find the position vector of the particle as a function of time. Homework Equations \vec{v}=\frac{d\vec{r}}{dt}...

hey, I know this might be abit silly, but u know the cauchy-reimann formula for a complex function to be diffrentiatable? here is a link to what I am talking about: http://en.wikipedia.org/wiki/Cauchy-Riemann_equations my question is: how do I write it in polar coordinates?:redface:

Hi. I have a pair of latitude and longitude (55.730397,12.358181) from Google Maps. I would like to convert it to POLAR COORDINATES in two-dimensional coordinate system. I am interested in the angle in the polar coordinates. I can't find any formula for this convertion? Thanks! /Taz

Homework Statement r = e^θ find arc length from (1,0) to origin Homework Equations ∫ab sqrt (r^2 + (dr/dθ)^2) dθ The Attempt at a Solution ∫10 sqrt ((e^θ)^2 + (e^θ)^2) dθ ∫10 sqrt (2(e^θ)^2) dθ ∫10 sqrt (2) (e^θ) dθ sqrt (2) ∫10 (e^θ) dθ need help converting limits in...

Homework Statement I'm considering Laplace's equation in 2D, written in circular polar coordinates (so that's u_rr + 1/r*u_r + (1/r^2)*u_theta,theta). I've worked out what all the seperable solutions are. My question is: is this set of seperable solutions complete. (That is, can all...

Homework Statement Hi, i am trying to find the div, grad and curl in cylindrical polar coordinates for the scalar field \ phi = U(R+a^2/R)cos(theta) + k*theta for cylindrical polar coordinates (R,theta,z) I have attempted all three and would really appreciate it if someone could tell me...

Homework Statement Semi circle of Radius R given. Find center of mass using polar coordinates, not double integrals. Homework Equations .5 intergral(r^2dpheta) (1/M) integral y dm r=R The Attempt at a Solution .5(2/piR^2) integral(R^3sinpheta do pheta) from 0 to pi, when I evaluate it I...

Homework Statement Consider a curve in R2 given in polar coordinates r=r(θ) for θ1<= θ <= θ2. Show that the line integral is equal to the integral from θ1 to θ2 of f(r*cosθ, r*sinθ) sqrt (r^2 + (dr/dθ)^2) dθ Homework Equations x= cos θ, y= sin θ The Attempt at a...

Homework Statement find limit if exist, or not then why f(x,y) = xy / sqrt(x2+y2) as (x,y) --> (0,0) The Attempt at a Solution can i change to polar coordinates x=rcost y=rsint so f(r,t) = rcostsint so as x,y tends to 0, r t will tend to 0 too?but cos(t) at 0 gives me 1...

How will you graph θ=π/4? In polar coordinates you can graph an equation like, r=a(1-sinθ) which gives a cardioid graph. But when my teacher giving me a class of sketching in polar coordinates then he ask to sketch θ=π/4. But as we know that in polar coordinates (r,θ). so in θ=π/4, there is...

After doing various searching through the google, most of the circular error probability I found are expressed interm of \sigma_x and \sigma_y, which the CEP(circular error probability) usually looks like (assume normal distribution): P(r) = \int\int...