heh

@Secret It's a secret ;)

Morning

In this question the answer says to take $\phi$ equal to zero. What is the reason for that?

In Griffith's, we have electric field of em wave in vacuum in the form of exponential and elsewhere the equation is described in terms of cosine. How?

I mean $e^(i\theta)$=$\cos\theta+ i\sin\theta$

Then what happened to the sun part?

Sin*

@Korra Do you want to prove that?

No I want to know the process

@Korra whose?

I don't just want to accept the transformation from exponential to cosine

The cosine is the real part

I want to know how it was done

So we just ignore the imaginary part?

@Korra You don't want $e^{i \theta} = \cos \theta + i \sin \theta$?

@Korra no

@Korra use vectors instead

So it's been a while since I've done EM but I'm fairly certain the imaginary part is convenience

No I don't want that proof

@AbhasKumarSinha as in?

@Korra If you don't want to use euler's identity, then you may use vectors instead

@AbhasKumarSinha He/She's asking why we don't care about the imaginary part

@SirCumference We care!

do we though

I am just wondering where sin function was thrown away and why

i'm trying to remember if classical EM waves have the same motivation of using complex numbers as QM does

@Korra real part $\hat i$ + imaginary part $\hat j$

That's ^ it

@SirCumference no

I actually wanted to get the expression of the potential from the expression of em fields

So I went the reverse way

@Korra If you show me that particular part of the book using a picture, then I may be helpful then.

I assumed a potential and got the em field but in cosine form

I don't know how to post pictures in chat

@Korra Then keep it in cosine form, no problem.

@Korra use upload button without writing any text in chat box.

I am on my cell and not pc

@Korra ok then wait

@Korra upload the image to imgur.com/upload then paste the link here, image will come.

Also I went this way because I don't know how to handle d'Alembertian inhomogeneous equation

@Korra I dun know much about that equation.

The lorenz gauge equation

@Korra not read...

$\blacksquare$

there we go

imgur.com/a/7ZDAjWE

@Korra eqn number?

I wanted to solve this

10.13& 10.14

imgur.com/a/33r8JTZ

9.43

@Korra seems very absurd.

@Korra Then what's your problem? That the potential you calculated has 0 in real part and rest everything is in imaginary part?

is that your problem?

I never calculated the potential

I assumed an oscillating potential (because em fields are oscillating) and got em fields in vacuun

@Korra then what?

@Korra No idea then.... :(

@dmckee Can you help @Korra ?

I am just saying that we have em fields I vacuum and we have two expressions of it:one exponential and other sinusoidal. I just want to know how we got from exponential to sinusoidal

I know Euler's Identity but it has an extra $i\sin\theta$ term in it

I'm reading about reactive ai machines and it says they don't have a concept of past nor future. They only deal with the present information, they use it to predict FUTURE outcomes and therefore they have a concept of future (even though it's predicted only from the present stimulus)

Why do they say it has no concept of the future when it uses present information to predict future outcomes? (or in terms of IBM chess machine, the next best move)

@NovaliumCompany Chaos Theory Implemention with Regression

@skullpatrol @skillpatrol Can you give something that makes me laugh? I really need your unique humor now

@Knight ye he does have that

@AbhasKumarSinha thanks for this random combination of words that you assumed I knew. Guess I'll be looking into chaos theory yay

@AbhasKumarSinha How plotting a regression curve on a graph with chaos points explains anything about my question?

cc @NovaliumCompany

:D

@NovaliumCompany You are too funny. Your words "thanks for this random combination of words that you assumed I knew" really made me laugh.

@skullpatrol I want your own. Martin Sleziak is funny but your humor is always on the point. Your xmas tree, ymas tree and zmas tree is still a topic of laugh in my family.

@ACuriousMind, merry Christmas, and happy new year!

@YuvrajSingh... Thanks, to you too!

@ACuriousMind

@Knight thx i guess :P

@YuvrajSingh... you too

@NovaliumCompany @danielunderwood merry Christmas and Happy new year!

@YuvrajSingh... What you doing ?

I finished my assignment, watching YouTube videos!

@Knight

I think you are thinking about Christmas party nah! I am in college hostel.

@YuvrajSingh... Merry Christmas to you too 🎄🎁

@JohnRennie Hey john rennie...idk if you remember me...we used to discuss problems in problem solving strategies during my jee prep....I have gone off for a while...needed time to get adjusted to my college and stuff...i just started sem 2...BTW Im in an engineering college, but i wanna study physics,especially theoretical physics.I'm having trouble finding right stuff to study ...I dont know where to start and what all to study...

@JohnRennie I have few books with me now:griffiths intro to Q.Mech,electrodynamics,special thepry of relativity from einstein to strings...I wanna start these books,but before I do I need some advice...I dont have anyone who can help me right now.so I really wish you help me through this

@Archer hi.

I am too from engineering back ground.

And physics lover.

@ayc for you. Which college.

Typing error.

@YuvrajSingh... Thanks, tho it's Hanukkah for me

@FakeMod The difference is that engineering school resembles high school math a lot more than math major classes :P

@YuvrajSingh... No don't worry about it. :) Merry Christmas And A Happy New Year! :)