Polar form Definition and 101 Threads

  1. R

    A Converting this vector into polar form

    In the following%3A%20https://pubs.rsc.org/en/content/articlehtml/2013/sm/c3sm00140g?casa_token=3O_jwMdswQQAAAAA%3AaSRtvg3XUHSnUwFKEDo01etmudxmMm8lcU4dIUSkJ52Hzitv2c_RSQJYsoHE1Bm2ubZ3sdt6mq5S-w'] paper, the surface velocity for a moving, spherical particle is given as (eq 1)...
  2. P

    Help graphing Vectors in polar form

    The equation I'm trying to graph on desmos is this with A & B as numbers, but I'm unsure how as it is a vector. r = (A cosθ sinθ cscθ - B sinθ cscθ) i + (A cosθ sinθ cscθ + B sinθ cscθ) j
  3. srfriggen

    I Cartesian to Polar form.... Is it just a transformation of the plane?

    Hello, Today I started to think about why graphs, of the same equation, look different on the Cartesian plane vs. the polar grid. I have this visualization where every point on the cartesian plane gets mapped to a point on the polar grid through a transformation of the grids themselves...
  4. A

    Complex numbers: convert the exponential to polar form

    Summary:: Hello, my question asks if the complex exponential equation 4e^(-j) is equal to 4 ∠-180°. I tried to use polar/rectangular conversions: a+bj=c∠θ with c=(√a^2 +b^2) and θ=tan^(-1)[b/a] 4e^(-j)=4 ∠-180° c=4, 4=(√a^2 +b^2) solving for a : a=(√16-b^2) θ=tan^(-1)[b/a]= -1 b/(√16-b^2)=...
  5. V

    Finding Polar Form Expressions: -3-3i & 2√3-2i

    Express -3-3i in polar form. I know that r=3√2. And I understand that now we take tan^-1(b/a) which I did. tan^-1(-3/-3) = π/4. So I put my answer as z = 3√2 [cos(π/4) + isin(π/4)]. However the answer manual told me this was incorrect I am unsure of where I went wrong...
  6. M

    MHB Finding the impedance in rectangular and polar form

    I don't fully understand how to work out the impedance from the given equation (5j-5)x(11j-11)/(5j-5)+(11j-11). Any help would be greatly appreciated. Thanks. The answer needs to be in rectangular and polar form.
  7. Mutatis

    Write ##5-3i## in the polar form ##re^\left(i\theta\right)##

    Homework Statement Write ##5-3i## in the polar form ##re^\left(i\theta\right)##. Homework Equations $$ |z|=\sqrt {a^2+b^2} $$ The Attempt at a Solution First I've found the absolute value of ##z##: $$ |z|=\sqrt {5^2+3^2}=\sqrt {34} $$. Next, I've found $$ \sin(\theta) = \frac {-3} {\sqrt...
  8. E

    MHB Convert another equation x^2+y^2=4 to polar form

    x^2+y^2=4 I have so far: (r^2)cos^(theta)+(r^2)sin(theta)=4 Idk what I'm supposed to do from here
  9. E

    MHB Convert equation 8x=8y to polar form

    Convert the equation to polar form 8x=8y I thought it would be 8*r*cos(theta)=8*r*sin(theta) Said it was incorrect then I thought I needed to divide by 8 to remove it, giving me: r*cos(theta)=r*sin(theta) But that was also incorrect and now I am stuck
  10. N

    Sinusoids as Phasors, Complex Exp, I&Q and Polar form

    Hi, I am going around in circles, excuse the pun, with phasors, complex exponentials, I&Q and polar form... 1. A cos (ωt+Φ) = Acos(Φ) cos(ωt) - Asin(Φ)sin(ωt) Right hand side is polar form ... left hand side is in cartesian (rectangular) form via a trignometric identity? 2. But then...
  11. T

    How do you always put a complex function into polar form?

    Homework Statement It's not a homework problem itself, but rather a general method that I imagine is similar to homework. For a given elementary complex function in the form of the product, sum or quotient of polynomials, there are conventional methods for converting them to polar form. The...
  12. T

    MHB Additional solution for polar form of complex number

    Hi, I had a question I was working on a while back, and whilst I got the correct answer for it, I was told that there was a second solution to it that I missed. Here is the question. ] I worked my answer out to be sqrt(2)(cos(75)+i(sin(75))), however, it appears there is a second solution...
  13. G

    B How to integrate a polar graph with respect to radius

    How is this done? My textbook only specifies integrating polar graphs with respect to theta.
  14. S

    MHB Complex Numbers - writing in polar form

    Hello everyone, I have a complex number problem that i would greatly appreciate some help with. Thanks in advance to anyone offering their time to make a contribution. Q) Write the following in polar form: I have attempted the question (please see my working below) and have been advised that i...
  15. A

    Converting standard to polar form

    Homework Statement you are given the standard form z = 3 - 3i Homework EquationsThe Attempt at a Solution so to convert this to polar form, i know that ##r = 3√2## but how do i find theta here? There are so many mixed answers it seems online that I can't tell... i know that ##(3,-3)## is in...
  16. M

    Is r,theta Equivalent to cos(theta)+isin(theta) in Complex Numbers?

    Homework Statement well this is not exactly a homework, i had an argument whith my teacher about my grade in a test, because i put a complex number in the form of R,theta and she claims that the form was costheta+isentheta, and i know that but i need to prove in a book that...
  17. rabualeez

    I Interesting question: why is ln(-1) in polar form....?

    Hi all, I was doing some math and I stumbled upon a very interesting thing. When I do ln(-1), I get πi, and when I turn that into polar coordinates on the calculator, it gives me πeiπ/2 . Why is that? I'm very curious to know, because they are so intertwined! Thank you
  18. javii

    Finding the polar form of a complex number

    Homework Statement Homework Equations r=sqrt(a^2+b^2) θ=arg(z) tan(θ)=b/a The Attempt at a Solution for a)[/B] finding the polar form: r=sqrt(-3^2+(-4)^2)=sqrt(7) θ=arg(z) tan(θ)=-4/-3 = 53.13 ° 300-53.13=306.87° -3-j4=sqrt(7)*(cos(306.87+j306.87) I don't know if my answer is correct...
  19. M

    Turning Complex Number z into Polar Form

    Homework Statement \frac{z-1}{z+1}=i I found the cartesian form, z = i, but how do I turn it into polar form?The Attempt at a Solution |z|=\sqrt{0^2+1^2}=1 \theta=arctan\frac{b}{a}=arctan\frac{1}{0} Is the solution then that is not possible to convert it to polar form?
  20. C

    Circled Part Formula in Double Integral: Explaining the Use of dA in Polar Form?

    Homework Statement can someone explain about the formula of the circled part? Why dA will become r(dr)(dθ)? Homework EquationsThe Attempt at a Solution A = pi(r^2) dA will become 2(pi)(r)(dr) ? why did 2(pi) didnt appear in the equation ?
  21. karush

    MHB Solving Polar Form of $\sin x$: Simple Equations

    $$y=\sin\left({x}\right) $$ write in polar form This reduces to $$r=1$$ So that's not = plots Not sure why I can't get these simple equations
  22. karush

    MHB Can the Polar Form of $y=x^3$ be Plotted on W|A?

    $y=x^3$ in polar form I got to this but it didn't plot ${x}^{3}$ $$r=\pm\sqrt{\frac{\sin\left({x}\right)}{\cos^3\left({x}\right)}}$$
  23. astrololo

    Finding polar form of complex number

    Homework Statement I have the following complex numbers : -3,18 +4,19i I must put it in polar form. Homework Equations r=(a^2+b^2)^(1/2) cos x = a/r sin x = b/r The Attempt at a Solution I was able to find with cos x = a/r that the x = 127,20 But when I do it with sin x = b/r I obtain like...
  24. kostoglotov

    Gravity of a disk acting on a mass on the z axis

    Homework Statement A lamina has constant density \rho and takes the shape of a disk with center the origin and radius R. Use Newton's Law of Gravitation to show that the magnitude of the force of attraction that the lamina exerts on a body of mass m located at the point (0,0,d) on the positive...
  25. S

    Understanding Phasors: How to Sketch a Voltage Phasor in Polar Form

    Hello Excuse me, but how do I sketch the phasor of a voltage that it's V=5cos(10t+30degrees) and how the V=5sin(10t+30degrees) ? I know that these can be converted as the R<angle polar form, with R being the Vmax, ie the 5, and the angle the phase. But what doesn't it matter if I have cos or...
  26. David Carroll

    Calculators Graphing in polar form on the TI-81

    Greetings. I have been teaching myself Calculus. To do this I ordered a used Larson's 8th Edition Calculus and a used TI-81 graphing calculator. When I got to Chapter 10, I ran into a problem: the chapter introduces equations in polar form and when I whipped out my TI-81, I had no idea how to...
  27. P

    Complex Numbers converting from Polar form to Acos(wt + x)

    Homework Statement "Put each of the following into the form Acos(ωt+θ)..." (a.) 4ejt+4e-jt Homework Equations Euler's Identity: ejθ = cos(θ)+jsin(θ) Phasor Analysis(?): Mcos(ωt+θ) ←→ Mejθ j = ej π/2 Trignometric Identities The Attempt at a Solution I attempted to use phasor analysis to...
  28. N

    MHB Converting from Cartesian to polar form

    another question: convert $|\frac{1-i}{3}|$ to polar form i am getting $\frac{\sqrt{2}}{3} e^{\frac{i\pi}{4}}$ but the solutions say: $e^{\frac{-i\pi}{4}}$ i did $ x = r\cos(\theta)$ and $y=r\sin(\theta)$ so $\frac{1}{3} = {\frac{\sqrt{2}}{3}}\cos(\theta)$ $\frac{1}{3} = \cos(\theta)$ And...
  29. N

    MHB What is the correct way to convert to polar form?

    I started of with attempting to convert the numerator first $ | 1 + i | = \sqrt{1^2+i^2}$ $= \sqrt{1-1} = 0$ ? this is wrong obviously, i don't see why its $\sqrt{2}$ for the second part $ |\sqrt{3} - i|= \sqrt{3+1} = 2$ $ x = r \cos\theta$ $ y = r\sin\theta$ $x = 2\cos\theta$ $...
  30. C

    Line element under coordinate transformation to get polar form

    Homework Statement Hello Guys, I am reading Hobson's General Relativity and I have come across an exercise problem, part of which frustrates me: 3.20 (P. 91) In the 2-space with line element ds^2=\frac{dr^{2}+r^{2}d\theta^{2}}{r^{2}-a^{2}}-\frac{r^{2}dr^{2}}{{(r^{2}-a^{2})}^{2}} and...
  31. C

    Find phasor current (impedance, etc.), finding polar form

    Homework Statement A 90Ω resistor, a 32 mH inductor, and a 5μF capacitor are connected in series across the terminals of a sinusoidal voltage source Vs = 750cos(5000t + 30)V. Calculate the phasor current. Homework Equations phasor current i = V/Z V in polar form = (Magnitude)(cos a + j sin...
  32. T

    Write the polar form of a complex number in the form of a+ib

    Homework Statement 4{cos(13∏/6)+isin(13∏/6)} = 4((√3/2)+(i/2)) = 2√3+2i Homework Equations The Attempt at a Solution This is an example from my textbook. The part which I do not understand is how to convert the cos and sin of radians into those fractions. Any help is greatly appreciated.
  33. A

    Surds in polar form of imaginary number

    Homework Statement Find the polar form for zw by first putting z and w into polar form. z=2√3-2i, w= -1+i Homework Equations Tan-1(-√3/3)= 5∏/6 The Attempt at a Solution r= √[(2√3)2+(-2)2]=4 tanθ= -2/(2√3)=-1/√3=-√3/3=> acording to above... tan-1(-√3/3)= 5∏/6 so, in polar form z should be...
  34. D

    Write 1-2i in Polar Form - Solve Confusion

    Homework Statement How do I write 1-2i in polar form? Homework Equations The Attempt at a Solution I know r=√5, and when using x=rcosθ, I get angle of 63.43 or 296.57. However, when I take the sin inverse of-2/√5 I get -63.43. I am really confused.
  35. E

    Problem with limits of integration - converting double integral to polar form

    Homework Statement \int_0^2 \int_0^\sqrt{2x-x^2} xy,dy,dx I know the answer, but how does the 2 in the outer integral become pi/2?? I'm fine with everything else, I just can't get this...
  36. M

    Calculating Impedance and Power in AC Circuits

    Homework Statement An impedance 8 + j7 Ω is connected in parallel with another impedance of 5 + j6 Ω. this circuit is then connected in series with another impedance, comprising a resistance of 5 Ω in series with a capacitive reactance of 7 Ω. The complete circuit is then connected to 150...
  37. V

    Find the locus of a pt in polar form

    the question is showed below i know that x=rcos θ and y= rsinθ and x^2 + y^2 = R^2 but i just dun know how to find the locus is polar form any clue ?
  38. H

    Writing in polar form a complex number

    Homework Statement Write z = 1 + √3i in polar form Homework Equations z = r (cos\varphi + sin\varphii) The Attempt at a Solution Found the modulus by |z| = √4 = 2 Now I am stuck on this part of finding the argument: Tan-1 (√3) now I am not sure how to go from that to...
  39. S

    Cube Roots of 1 in Polar Form: Stephen's Question

    Hi all, There is a question that asks? Determine the cube roots of 1 in polar form? Does that mean I can use De Moirve Formula? Stephen
  40. R

    Writing x^2 + y^2 = 1 + sin^2(xy) in polar form

    Homework Statement Write the equation x^2 + y^2 = 1 + sin^2(xy) in polar form assuming x = rcos(\phi) y = rsin(\phi) 0<r, 0<= \phi < 2pi solve for r as a function of \phi The Attempt at a Solution (rcos(\phi))^2 + (rsin(\phi))^2 = 1 + sin^2(r^2cos(\phi)sin(\phi))...
  41. Darth Frodo

    Polar Form of Complex Numbers: Understanding Quadrants and Sign Conventions

    Not homework as such, just need some clarification. When finding \alpha do you have to take the signs into account when finding tan^{-1} x/a. Does it matter if a or x are negative? Next question is about quadrants 1: \theta = \alpha 2: \theta = \pi - \alpha 3: \theta = -\pi -...
  42. R

    Multiple integrals in polar form

    Homework Statement do you see how the integral of r is .5? I don't get how that follows?
  43. A

    Cauchy-Riemann equation polar form

    I couldn't find any book discussing all of this. =================================================== U+jV=f(x+jy) W=f(z) Ux=Vy Uy= -Vx jWx=Wy <--Cauchy-Riemann equation Uxx+Uyy=0 Vxx+Vyy=0 <--harmonic condition...
  44. C

    Help with finding the modulus, polar form and polar exponential form

    Homework Statement Consider the complex number z=(i^201+i^8)/(i^3(1+i)^2). (a) Show that z can be expressed in the Cartesian form 1/2+(1/2)i. (b) Find the modulus of 4z − 2z*. (z* meaning z-bar/complex conjugate of z) (c) Write 2z in polar form. (d) Write 8z^3 in polar exponential form...
  45. C

    Why Does Arg(z) of a Complex Number Differ in Solutions?

    Homework Statement express the arg(z) and polar form of (1/\sqrt{2}) - (i/\sqrt{2}) Homework Equations The Attempt at a Solution Ok so I did \sqrt{(1/\sqrt{2})^{2}+(1/\sqrt{2})^{2}} = 1 so tan^{-1}(1) = \pi/4 so arg(z)=5\pi/4 but they had the answer as -3\pi/4 Am I...
  46. I

    Complex Analysis: Using polar form to show arg(z1) - arg(z2) = 2n*pi

    Homework Statement Given that z_{1}z_{2} ≠ 0, use the polar form to prove that Re(z_{1}\bar{z}_{2}) = norm (z_{1}) * norm (z_{2}) \Leftrightarrow θ_{1} - θ_{2} = 2n∏, where n is an integer, θ_{1} = arg(z_{1}), and θ_{2} = arg(z_{2}). Also, \bar{z}_{2} is the conjugate of z_{2}. Homework...
  47. I

    Form an op w/ three vectors in polar form.

    Homework Statement I'm trying to find the best solution for solving a problem in which I must form an operation with three vectors in polar form, ending with a sum in rectangular form. The operation is as follows: (5 \angle 0°) + (20 \angle -90°) - (6 \angle180°) = Homework Equations...
  48. R

    How to convert velocity potential from polar form to Cartesian coordinate form

    Homework Statement Alright, here's the question, A stream function for a plane, irrotational, polar-coordinate flow is ψ=9r^2sin^θ. Find out the velocity potential in Cartesian Co-ordinate! Homework Equations The Attempt at a Solution Well, I can easily find out the velocity...
  49. N

    Transform explicit function to polar form

    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...
  50. N

    Finding the Smallest n for Real z^n in Complex Numbers

    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...
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