Question

laplace of e^t-tcos^2t

Answer 1

one day i have to learn how to do these

Answer 2

if you just need the answer it is here
http://www.wolframalpha.com/input/?i=laplace+of+e^t-tcos^%282t%29&a=*FunClash.laplace-_*LaplaceTransform.CalculateLaplace-&a=CoordinateSystem_*Cartesian2D.Cartesian3D-
maybe i cando this over the summer

Answer 3

Input is cos^2t nor cos 2t....

1/(s-1) - (s^4+2s^2+8)/(s^2(s^2+4)^2)

Answer 4

@satellite73 Laplace isnt all the mysterious.

The question is just asking: What do we get when we multiply this expression by \(e^-{st}\) and integrate if from 0 to infinity with respect to "t"?

When you get a chance, Arthur Mattuck does a simple and concise explanation of it:

http://www.youtube.com/watch?v=zvbdoSeGAgI

Answer 5

e^-{st} .... i see, I didnt but the - in the {..}

Answer 6

yeah i think i knew that, but i also seem to recall that you never actually use this method, but rather you use a bunch of properties that i do not know. since i don't really know much difeq the motivation for doing this is not clear to me either.
i will take a look at the link you sent, thanks
never was a big fan of "techniques of ___" though

Answer 7

Mostly use a bunch of tables in practice, I think....

Answer 8

"you'll get proficient in using this in the end of the next two weeks"!!! yeah, sure

Answer 9

yeah, the outcomes are so predictable that they set use tables to simplfy the process

at the begining of learning the laplace technique you are just learning how to move things about, afterwards it is applied to solving diffyQs

Answer 10

just as derivates are "ruled up" so that you dont have to limit it each time, the Laplace tables are a similar devise.

Answer 11

video is really quite good though isn't it!

Answer 12

im a fan :)

Answer 13

By the way, I got wolphramalpha as a paid desktop app for a couple euros from IntelApp.

Handy if u don't like the ads they keep sticking on there.

Answer 14

i can afford to click close more than i can afford to not click close

Answer 15

The other thing is my machine tends to cough a bit if I have OS and Wolfram going at the same time as a bunch of other tabs and it doesn't do it when I have it on desktop.

Answer 16

youtube has the lecture split in 2 parts; the second part is:

http://www.youtube.com/watch?v=hqOboV2jgVo&feature=relmfu