Describe the Riemann surface for .w=z

Short Answer

Expert verified

R=r12and2ϕ=θ

Step by step solution

01

Riemann surface hypothesis

Formula from Riemann surface hypothesis:

w=Reiϕandz=reiθ

If z=reiθwithr>0

w=lnr+iθ

It's one logarithm of z.

Adding integer multiples of2πI .

w=lnr+iθ+2nπ,nZ

02

Use Riemann surface hypothesis

Function is given as w=z

Let's assume the following forms as follows:

z=reiθ ...... (1)

w=Reiϕ ...... (2)

To find the surface w first change r how that impact on R .

w=z ...... (3)

Put (1) and (2) in equation (3) as follows:

Reiϕ=reiθ

Reiϕ=r12e12iθ

By equating each like terms, we get

R=r12Andϕ=θ2 or 2ϕ=θ

03

Put different values of  R

So if r = constant for example, r = 1 and it keeps changing the value of θ then the value of ϕ will change 3 times ofθ. For example, if θ=π then the image of it will be theϕ=π2.

If r changes for example, r = 2 and keep the value of θ constant then the value of R be r12=1.41.

If r changes for example r = 2 and keep changing the value of θ then the value of ϕ will changes 3 times, for example, if θ=π then the image of w will be theϕ=π2 .

Hence, R=r12and2ϕ=θ .

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

To prove that the Jacobian of the transformation is (u,v)(x,y)=|f'(z)|2 using Cauchy- Reimann equations.

Compare the directional derivative dϕds (Chapter 6, Section 6) at a point and in the direction given by dz in the z plane, and the directional derivativedϕds in the direction in the w plane given by the image dw of dz . Hence show that the rate of change ofTin a given direction in the z plane is proportional to the corresponding rate of change of T in the image direction in the w plane. (See Section 10, Example 2.) Show that the proportionality constant is|dwdz| . Hint: See equations (9.6) and (9.7).

Let f(z) be expanded in the Laurent series that is valid for all z outside some circle, that is,|z|>M(see Section 4). This series is called the Laurent series "about infinity." Show that the result of integrating the Laurent series term by term around a very large circle (of radius > M) in the positive direction, is 2πib1(just as in the original proof of the residue theorem in Section 5). Remember that the integral "around " is taken in the negative direction, and is equal to 2πi: (residue at ). Conclude thatR()=-b1 . Caution: In using this method of computingR() be sure you have the Laurent series that converges for all sufficiently large z.

To find: uand v as a function of x and y & plot the graph and show curve u = constant constant should be orthogonal to the curves v = constant . w = sin z

Use the following sequence of mappings to find the steady state temperature T(x,y) in the semi-infinite strip y0,0xπ if T(x,0)=1000,T(0,y)=T(π,y)=0and T(x,y)0as y. (See Chapter 13, Section 2 and Problem 2.6.)

Usew=(z'-1z'+1)to map the half plane v0on the upper half plane y'>0, with the positive axis corresponding to the two rays x'>1and x'<-1, and the negative yaxis corresponding to the interval -1x1of the x'axis. Use z'=-coszto map the half-strip0<x<π,y>0on the Z'half plane described in (a). The interval role="math" localid="1664365839099" -1x'<1,y'=0corresponds to the base0<x<π,y=0of the strip.

Comments: The temperature problem in the (u,v) plane is like the problems shown in the z plane of Figures 10.1 and 10.2, and so is given by T=(100π)arctan(vu). In the z plane you will find T(x,y)=100πarctan2sinxsinhysinh2y-sin2x

Put tanα=sinxsinhy and use the formula for tan2αto get T(x,y)=200πarctansinxsinhy" width="9" height="19" role="math">

Note that this is the same answer as in Chapter 13 Problem 2.6, if we replace 10 by π.

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free