# Recent content by physicsnewb7

1. ### I don't understand the meaning of f^(39)(pi/2)?

every fourth derivative gives you sin(x) I think you can take it from there
2. ### I don't understand the meaning of f^(39)(pi/2)?

I think they mean take the 39th derivative of sin(x) and evaluate that at pi/2 the 2nd derivative -sin(x) third is -cos(x) and fourth is sin(x)......
3. ### Why was Tesla obsessed with the number 3?

I agree. The history channel once upon a time fell in the 0.1% but now...ancient aliens and swamp people lol. The only documentaries I trust now are on science channel.
4. ### Why was Tesla obsessed with the number 3?

It's mentioned in the documentary about tesla on the history channel. The name of the documentary is "The History Channel-Modern Marvels:Nikola Tesla:Mad Electricity." Mind you they also air ancient aliens so much its as if they believe aliens were apart of everyday life in antiquity.
5. ### Laurent series and partial fractions

Homework Statement find the laurent series of sin(2z)/(z^3) in [z]>0 Homework Equations The Attempt at a Solution I am completely confused. I can understand some of the examples given on laurent series, like using partial fractions and then finding geometric series. Do I rewrite...
6. ### Complex analysis

ohhhhh nevermind i finally got it you rewrite the denominator as (z+i)(z-i) then do the partial fraction. so simple! you were right rizardonthanks
7. ### Complex analysis

So I do the partial fraction after i expand out? expanding (z+i)/(z^2+1) I get (x+yi+i)/(x^2+2xyi-y^2+1) how am I supposed to factor the denominator?
8. ### Complex analysis

all i want is a simple hint i don't want anyone to do the problem for me I just want a little help. just a little push in the right direction would be so helpful.
9. ### Complex analysis

Homework Statement write f(z)= (z+i)/(z^2+1) in the form w=u(x,y)+iv(x,y) Homework Equations The Attempt at a Solution I tried using the conjugate and also expanding out algebraically but I can not seem to get the right answer. I know what the answer is...
10. ### Keys are locked

it turns out that that individual spilt something on it. he just confessed, so a new keyboard it is....
11. ### Laplace inverse

which one??????
12. ### Laplace inverse

Homework Statement s2/((s2-1)(s-1)2) Homework Equations laplace tables The Attempt at a Solution I attempted the shifting method and also partial fraction method but efforts were fruitless
13. ### Keys are locked

Someone hit some random combination of keys that locked up some of the keyboard. A few of them started working but there is still a couple that don't work. Does anyone know how to unlock these keys?:uhh:
14. ### Simple differential equation

Thank you very much you have been very helpful. I appreciate it
15. ### Simple differential equation

oh yeah i know i put cos by accident, but that is the solution right? I arrived at this solution by a long trial and error method. any way to quickly get at it in general?