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/sci/ - Science & Math

File: 859 KB, 1296x797, 1494357912616.png [View same] [iqdb] [saucenao] [google]

Anonymous Wed May 24 13:46:31 2017 No.8932789 [Reply] [Original]

Good ol' /sci/ humor thread
more like pic related pls.

>>	Anonymous Wed May 24 13:46:52 2017 No.8932792 File: 744 KB, 1299x872, 1494358668704.png [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 13:48:01 2017 No.8932793 File: 534 KB, 960x600, veritasium 0.png [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 13:50:49 2017 No.8932800 File: 80 KB, 960x601, veritasium 1.jpg [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 13:52:08 2017 No.8932804 File: 458 KB, 960x595, veritasium 2.png [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 14:10:48 2017 No.8932846 File: 366 KB, 890x343, brainletsBTFO.png [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 14:12:28 2017 No.8932851 File: 381 KB, 3264x2448, brainletsBTFO2.jpg [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 14:22:58 2017 No.8932867 File: 110 KB, 1342x436, calculus.png [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 14:32:21 2017 No.8932898 File: 34 KB, 480x853, tmp_403-1495611669609-748197226.jpg [View same] [iqdb] [saucenao] [google] EZ AF

>>	Anonymous Wed May 24 14:34:07 2017 No.8932902 File: 296 KB, 500x375, 1477517709683.png [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 14:34:45 2017 No.8932904 [eqn](f\cdot g)'(x) = f'(x)g'(x) + C [/eqn]

>>	Anonymous Wed May 24 14:47:33 2017 No.8932929 File: 41 KB, 724x524, 1487715579224.png [View same] [iqdb] [saucenao] [google] >>8932902

>>	Anonymous Wed May 24 14:50:52 2017 No.8932934 File: 201 KB, 974x1238, 1473779747243.jpg [View same] [iqdb] [saucenao] [google]

>>	Anonymous Wed May 24 14:53:11 2017 No.8932938 >>8932904 QUICK EXERCISE FOR THE ENTIRE BOARD Find all real functions such that the equality [math] (f\cdot g)'(x) = f'(x)g'(x) [/math] holds. If you can't do this then leave this board immediately.

>>	Anonymous Wed May 24 14:54:47 2017 No.8932944 >>8932934 The border collie looks like Einstein.

>>	Anonymous Wed May 24 14:56:12 2017 No.8932948 >>8932938 no such function exists LIAR

>>	Anonymous Wed May 24 15:01:08 2017 No.8932954 File: 91 KB, 960x468, 1474108903999.jpg [View same] [iqdb] [saucenao] [google]

Anonymous Wed May 24 15:02:26 2017 No.8932956

>>8932948
And that's why we have the empty set. That said, you have not given any proof so what you are saying is worth less than dog shit.

Anyway, let me re-state my problem formally.

[math] \text{Characterize the set } A = \{ (f,g) \in (C^1 ( \mathbb{R} ))^2 : (f\cdot g)'(x) = f'(x)g'(x) \} [/math]

In other words, find all pairs of functions such that they have that property.

>>	Anonymous Wed May 24 15:03:05 2017 No.8932958 File: 235 KB, 852x805, 1469139928486.jpg [View same] [iqdb] [saucenao] [google] >>8932954

>>	Anonymous Wed May 24 15:06:44 2017 No.8932966 File: 556 KB, 1464x1665, 1468987376047.jpg [View same] [iqdb] [saucenao] [google] >>8932956

>>	Anonymous Wed May 24 15:07:54 2017 No.8932969 >>8932948 f = g = R->R x->0

>>	Anonymous Wed May 24 15:09:15 2017 No.8932971 >>8932938 f=0, g arbitrary C1 function or the other way around

>>	Anonymous Wed May 24 15:19:05 2017 No.8932989 >>8932956 [math]A=\mathbb{R}[/math] t: wildberger

>>	Anonymous Wed May 24 15:27:44 2017 No.8933002 >>8932971 That's the trivial solution. If you think it is the only one, prove that no other element can be in the set.

>>	Anonymous Wed May 24 15:34:31 2017 No.8933010 >>8932958 >>8932966 Where's the joke?

>>	Anonymous Wed May 24 15:38:27 2017 No.8933016 >>8932956 f(x) = e^x g(x) = x

>>	Anonymous Wed May 24 15:43:29 2017 No.8933020 >>8933016 Correct!

>>	Anonymous Wed May 24 15:44:36 2017 No.8933024 File: 1.36 MB, 1674x3929, 1469128821857.jpg [View same] [iqdb] [saucenao] [google] >>8933010

>>	Anonymous Wed May 24 15:46:11 2017 No.8933026 >>8933024 So this is /int/ humour? I'm guessing you didn't see what board we're on?

>>	Anonymous Wed May 24 15:48:07 2017 No.8933028 File: 93 KB, 640x664, global+warming+obama+politics+13450769231404944437.jpg [View same] [iqdb] [saucenao] [google] >>8933026

>>	Anonymous Wed May 24 18:17:29 2017 No.8933357 >>8933028 Is it funny because it's scientifically illiterate?

>>	Anonymous Wed May 24 18:23:00 2017 No.8933366 >>8933357 Are you seriously responding to obvious /pol/ b8 newfag?

>>	Anonymous Wed May 24 18:24:40 2017 No.8933371 >>8932971 of they could both be arbitrary constant functions

>>	Anonymous Wed May 24 18:29:29 2017 No.8933379 >>8932934 >>8932954 >>8932958 >>8932966 >>8933024 /pol/ get out of here please

>>	Anonymous Wed May 24 18:45:28 2017 No.8933400 >>8932938 f=Id and g in C1

>>	Anonymous Wed May 24 18:55:04 2017 No.8933417 File: 235 KB, 1203x1447, 1487088398070.jpg [View same] [iqdb] [saucenao] [google] >>8933379 i smell jew

Anonymous Wed May 24 19:14:24 2017 No.8933456

>>8932938
Right.
Suppose [math] f'\cdot g + f \cdot g' = f' \cdot g' [/math]. Divide through by [math] f \cdot g [/math]. You're left with [math] \ln(f)' + \ln(g)' = ln(f)' \ln(g)' [/math]. This is easily solved for ln(g)' : [math] \ln(g)' = 1 - \frac{1}{\ln(f)' - 1}. [/math].
Choose an f and you can solve this for g. Probably need to take care about the interval where they're defined but this should give the non-trivial solutions.

>>	Anonymous Wed May 24 19:18:02 2017 No.8933461 >>8933456 Nice

>>	Anonymous Wed May 24 19:21:02 2017 No.8933467 >>8933456 wrong >>8933016

>>	Anonymous Wed May 24 19:25:03 2017 No.8933470 >>8933456 Should've been 1+ instead of 1-, whoops.

>>	Anonymous Wed May 24 19:26:36 2017 No.8933474 >>8933456 >>8933467 Fucked up with my babby algebra: you end up with [math] \ln(g)' = \frac{\ln(f)'}{\ln(f)' - 1}. Simplify that as you wish, or not, plug in an f, and solve for g.

>>	Anonymous Wed May 24 19:27:49 2017 No.8933476 >>8933456 >>8933467 Fucked up with my babby algebra: you end up with [math] \ln(g)' = \frac{\ln(f)'}{\ln(f)' - 1} [/math]. Simplify that as you wish, or not, plug in an f, and solve for g.

>>	Anonymous Wed May 24 19:28:13 2017 No.8933477 File: 408 KB, 500x3920, aYbWbXw_700b.jpg [View same] [iqdb] [saucenao] [google]

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