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2023-11: Warosu is now out of extended maintenance.

/sci/ - Science & Math

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Anonymous Wed Mar 20 13:34:24 2019 No.10483431 [Reply] [Original]

FUCK fourier transforms

>>	Anonymous Wed Mar 20 13:36:30 2019 No.10483434 >>10483431 It's just a change of basis

>>	Anonymous Wed Mar 20 13:47:00 2019 No.10483456 i think their pretty good

>>	Anonymous Wed Mar 20 14:07:57 2019 No.10483503 >>10483431 What's giving you trouble there, sport?

>>	Anonymous Wed Mar 20 14:09:34 2019 No.10483506 >>10483431 You're right, Laplace transforms are so much sexier

>>	Anonymous Thu Mar 21 00:04:14 2019 No.10484941 File: 740 KB, 692x1024, ezgif-2-5580603c26bc.png [View same] [iqdb] [saucenao] [google] >>10483431 Do FFT instead.

Anonymous Thu Mar 21 09:09:01 2019 No.10485659
File: 114 KB, 1024x712, B89103E32687426E9F18C96738696971.jpg [View same] [iqdb] [saucenao] [google]

Just seet the e^-i2πtheta as a phasor i.e just see it as a sine function. Basically you are just dividing by a wave and asking how much of this wave is part of the other wave.

>>	Anonymous Thu Mar 21 09:10:17 2019 No.10485661 >>10485659 >>10483506 lmao look at these retards , spotted the engineers

>>	Anonymous Thu Mar 21 09:11:46 2019 No.10485663 File: 657 KB, 500x375, Fourier.gif [View same] [iqdb] [saucenao] [google] >>10483431

Anonymous Thu Mar 21 09:23:32 2019 No.10485684

>>10485661
desu a laplace transform fourier transform is a mathematical subset of laplace transforms with the real component set to zero over symmetric bounds. Both are useful in their areas, I had Fourier stuff show up more in more elementary physics because it maps frequency and amplitude, but a laplace transform is still really handy because it maps rate of change dependency into direct functional dependency

>>	Anonymous Thu Mar 21 09:24:18 2019 No.10485688 >>10485684 > fourier transforms are a subset of laplace transforms ?????

>>	Anonymous Thu Mar 21 09:35:27 2019 No.10485709 >>10485688 Yes

>>	Anonymous Thu Mar 21 09:36:55 2019 No.10485711 >>10485709 no. its wrong.

>>	Anonymous Thu Mar 21 09:37:44 2019 No.10485713 >>10485661 >t. i watched a 3blue1brown video

Anonymous Thu Mar 21 09:41:25 2019 No.10485717

>>10485711
The Laplace transform maps a functionf(t)to a functionF(s) of the complex variables, wheres=σ+jω

If we set the real part of the complex variablesto zero,σ=0 the result is the Fourier transformF(jω) which is essentially thefrequency domain representationoff(t) (note that this is true only if for that value ofσσthe formula to obtain the Laplace transform off(t) exists, i.e., it does not go to infinity)

>>	Anonymous Thu Mar 21 09:43:35 2019 No.10485719 I understand how it works but I can't get the right answers !

>>	Anonymous Thu Mar 21 09:46:05 2019 No.10485724 >>10485719 >doubt

>>	Anonymous Thu Mar 21 10:13:45 2019 No.10485776 >>10483431 I wish.

>>	Anonymous Thu Mar 21 10:16:12 2019 No.10485781 File: 11 KB, 224x224, download.jpg [View same] [iqdb] [saucenao] [google] >tfw analyst >tfw all this shit is trivial lmao engcucks on suicide watch

>>	Anonymous Thu Mar 21 15:21:08 2019 No.10486517 >>10483434 Isn't everything just a change of basis?

>>	Anonymous Thu Mar 21 15:50:30 2019 No.10486581 >>10483431 They're just a change of representation. Their most common applications are from a basis in direct space (x, y, z) to a basis in reciprocal space (px, py, pz) or from a time-domain analysis into a frequency-domain analysis.

>>	Anonymous Thu Mar 21 16:05:46 2019 No.10486609 >>10485711 based retard

>>	Anonymous Thu Mar 21 16:12:53 2019 No.10486627 >>10483431 Easy. They wrap around cylindrical objects just fine.

Anonymous Thu Mar 21 20:09:19 2019 No.10487131
File: 240 KB, 1600x1200, fast_and_fourier.jpg [View same] [iqdb] [saucenao] [google]

>>10483431
>>10484941
>tfw engineering undergrad taking signals with no clue what any of the shit actually means
>ace the course by memorizing how to work problems and use tables like a well-trained monkey
>finally get in a few analysis courses in grad school and realize what the hell was actually going on
they need to change this shit somehow

>>	Anonymous Thu Mar 21 20:10:21 2019 No.10487132 >>10487131 also, see this https://youtu.be/spUNpyF58BY you can at least get a primitive understand

>>	Anonymous Thu Mar 21 21:34:39 2019 No.10487255 >>10483506 No man, Z transforms are where it's at. Having to use an FFT to actually filter a signal is pleb tier when you can just pass each data through a live DSP algorithm.

>>	Anonymous Thu Mar 21 21:41:18 2019 No.10487273 >>10483431 They aren't even hard. Wavelet and Hilbert are much worse

>>	Anonymous Thu Mar 21 21:44:14 2019 No.10487280 >>10487131 Signals made perfect sense to me as an undergrad, dunno what was wrong with your class dude

>>	Anonymous Thu Mar 21 21:45:05 2019 No.10487283 >>10485688 Fourier is a subset of Laplace bro https://www.youtube.com/watch?v=S7zGQWX3FZQ

>>	Anonymous Thu Mar 21 22:41:00 2019 No.10487430 >>10487132 thank you

>>	Anonymous Thu Mar 21 23:18:00 2019 No.10487502 >>10483431 Why?

>>	Anonymous Fri Mar 22 00:05:07 2019 No.10487592 >>10487280 yeah it all made perfect sense to me in undergrad too.

>>	Anonymous Fri Mar 22 00:12:34 2019 No.10487600 >>10487283 Based Eugene coming in with the visualization https://www.youtube.com/watch?v=6MXMDrs6ZmA

>>	Anonymous Fri Mar 22 02:07:48 2019 No.10487783 I'm sitting in my analysis class thinking that I am going to learn about integrals or some shit, but the professor keeps talking about this weird flower transformer.

>>	Anonymous Fri Mar 22 02:12:23 2019 No.10487793 File: 319 KB, 256x256, Fourier_series_square_wave_circles_animation.gif [View same] [iqdb] [saucenao] [google] >>10483431

>>	Anonymous Fri Mar 22 02:15:53 2019 No.10487803 File: 171 KB, 374x347, 1455628653724.png [View same] [iqdb] [saucenao] [google] >>10483431 There a problem, OP?

Anonymous Fri Mar 22 03:03:39 2019 No.10487875

>>10487131
>I didn't understand it
>therefore it's for brainlets
Sounds to me like YOU are actually the brainlet, being unable to comprehend the logic behind the concepts at the time. One could argue that engineers are truly more intelligent than majors of pure sciences because not only are they able to reduce problems in complexity to the point where a viable real-world solution can be found, but they are also intelligent enough to understand the logical basis of the simplified problems presented to them without explicit explanation, whereas Maths majors have to be spoonfed all of the concepts and generalizations.

>>	Anonymous Fri Mar 22 03:09:40 2019 No.10487880 it's hilarious that engineers find fourier and laplace transforms difficult. engineers truly are retarded

Anonymous Fri Mar 22 22:13:14 2019 No.10489833
File: 174 KB, 367x385, A-Laue-diffraction-image-from-a-protein-crystal-collected-on-the-MAR345-image-plate.png [View same] [iqdb] [saucenao] [google]

I FUCKING HATE FOURIER TRANSFORMS IN STRUCTURAL BIOLOGY. WHY DID I GO INTO THIS FIELD IF I'M SUCH A BRAINLET AHHHHHHHHH

>>	Anonymous Fri Mar 22 22:20:37 2019 No.10489843 >>10489833 CT scans also use spacial fourier transforms, it's neat shit.

>>	Anonymous Fri Mar 22 22:21:10 2019 No.10489845 >>10487880 I find pretty much everything difficult

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