Nice job. That was slightly headachy, but not too bad ; )
@owlsmath3 күн бұрын
Yep! More headaches than guess and check for sure
@holyshit9223 күн бұрын
If you want integral to calculate try this \int \frac{x}{\sqrt{(x+2)^2+exp(x)}}dx Result should be x - 2ln(x+2+\sqrt{(x+2)^2+exp(x)})+C and it is quite interesting because programs like Mathematica or Wolfram alpha can't calculate it You can try this and record video about it
@owlsmath3 күн бұрын
Looks tough!
@holyshit9223 күн бұрын
@@owlsmath if you add zero , use linearity of integral and multiply by one you will see suitable substitution but the most interesting fact is that computer programs can't calculate it When you look at result this x suggest what kind of zero you should add and argument of ln suggest you what kind of one you should multiply
@holyshit9223 күн бұрын
x=3 is a solution but is it the only one
@HJ28_3982 күн бұрын
I don't know the proper way to do it, but just doing some Desmosing, I've found that around 3.44983 - 7.89905i and 3.44983 + 7.89905i are two of these such answers, you are correct 👏👏.
@CyrusislikeawsomeКүн бұрын
I guess proving it with the W function kinda helps that because you can see via the graph
@reaperskyfall66914 күн бұрын
After seeing this my brain 🧠: please pull out calculator 100ms
@owlsmath3 күн бұрын
Is that 100 milliseconds? Your brain reacted fast!
@reaperskyfall66913 күн бұрын
@@owlsmath no sir I mean cal-c type 100ms
@owlsmath3 күн бұрын
Oh I see!
@nizogos4 күн бұрын
The x=3 solution is visible,after that you could move all the terms of your equation to one side and define a function.From there you could prove that the function is monotonous through its derivatives and thus x=3 is a unique solution
@owlsmath4 күн бұрын
yep makes sense!
@taterpun62113 күн бұрын
At least for real numbers. Lambert W function has infinite branches like logz
@owlsmath3 күн бұрын
@@taterpun6211 right always infinite number of complex solutions
I Feynmanned this one instead, with e^(- ax) then did the Euler form of sin(3x). One thing I missed was the neat use of arctan(1/x) at the end - I like that.
@owlsmath5 күн бұрын
hey adandap. Nice you turned Feynman into a verb! thanks :)
@adandap5 күн бұрын
@@owlsmath Wait til you meet my mate 'Fractional Feynman'!
@owlsmath5 күн бұрын
@@adandap ha! Saw your email and I got scared when I saw your paper. 🤣
@holyshit9225 күн бұрын
I would use integration by parts u = sin^2(x) , dv = 1/x^2dx then use double angle formula sin(2x) = 2sin(x)cos(x) then we can use substitution t = 2x Finally calculate L(sin(t)/t) and plug in s =0
@owlsmath5 күн бұрын
Nice method. That gets around the messiness of using the L(f(t)/t) twice
@doronezri10435 күн бұрын
Excellent use of the fundamental properties of Laplace Transform 🍻
@owlsmath5 күн бұрын
Thanks Doron. Cheers! 🍻
@par225 күн бұрын
Could you do Lobachevsky's rule on this?
@owlsmath5 күн бұрын
Hi Par. I don’t think so unless you can manipulate it to a different form. The 3x in the sin function is no problem and easily fixed by substitution but the trouble is e^-2x is not even or pi periodic
@holyshit9225 күн бұрын
I would use Laplace transform
@par225 күн бұрын
@@owlsmath Ah ok, thanks!
@nathanmarchant-fh9uw5 күн бұрын
cool integral, tried to solve it myself but changing variable mid integration always throws me off a bit
@owlsmath5 күн бұрын
Hi Nathan. Thanks! 👍👍👍
@RealQinnMalloryu46 күн бұрын
In^x^e^x(x)^2In^x^e^x/In^x^e^x{x+x ➖}+In^x^e^x{1+1 ➖}=x^2/In^x^e^x{x^2+2}w^{In^x^e^xdx^n ➖ 2/dx^2n ➖ 2In^x^e^xdx^ n ➖ 2/dx^2n ➖ 2}^w =w^{In^x^e^x^dx^2n ➖ 4/dx^2n ➖ 4In^x^e^x^dx^2n ➖ 4/dx^2n ➖ 4}^w=w^{In^x^e^x^dx^2n ➖ 2^2/dx^2n ➖ 2^2In^x^e^x^dx^2n ➖ 2^2/dx^2n ➖ 2^2}^w=w^{In^x^e^x^d^x^1n ➖ 1^1/dx^1 n ➖ 1^1In^x^e^x^dx^1n ➖ 1^1/dx^1n ➖ 1^2}^w=dx^1n ➖ 2 (w^{In^x^e^xdx^n ➖ 2piIn^x^e^x^dx^n+1}^w). i liked the video i watched enjoyed thank fir Laplace transformation method substituted.
@yasserboulanouar12896 күн бұрын
I haven't studied laplace transform so I'm wondering can you also do it with integration by part ( talking abt ue^-un)?
@owlsmath6 күн бұрын
Hi Yasser. Yes, you can. I derived the formulas in a previous video but the method is integration by parts. So just takes a little longer. If you're interested here's the playlist: kzbin.info/aero/PLOvxeHw2nLaySIKdV-QTjiGHHkOx0M_2-
@yasserboulanouar12896 күн бұрын
@owlsmath thanks ill check it out
@slavinojunepri76487 күн бұрын
We could expand 1/(1+x) into a geometric without the exponential substitution to get the result.
@owlsmath7 күн бұрын
HI Slavino. Makes sense but would you need to do the substitution later? Or does the integral work ok without it?
@edmundwoolliams12407 күн бұрын
You'd need to make the same substitution again later, yeah
@holyshit9224 күн бұрын
@@owlsmath after geometric series expansion all we need to do is change the order of summation and integration then integration by parts And it seems that we will get Catalan constant as result
@owlsmath4 күн бұрын
@@holyshit922 interesting. Oh because with IBP d(ln x) = 1/x so when you integrate x^n it cancels. I better do it on paper :)
@doronezri10438 күн бұрын
Excellent! Two of my favorite techniques - geometric sum and Laplace🍻
@owlsmath8 күн бұрын
yep me too. Thanks!
@zechariahwilson99947 күн бұрын
omg control theory LMFAOOOOO I LOVE THIS GAME
@owlsmath7 күн бұрын
@@zechariahwilson9994 whats going on?
@waarschijn8 күн бұрын
Nice, very similar to the one you did on owl3.
@owlsmath8 күн бұрын
oooh didn't think of that but yes. thanks :)
@dean5328 күн бұрын
This is something 🎉
@owlsmath8 күн бұрын
Hi Dean. Thanks!
@holyshit9228 күн бұрын
In my opinion the best way to calculate this integral is to factor out sqrt(5) from denominator of the integrand and use substitution sqrt(x^2+6x+8) = u - x But if we want result presented on video it would be better to use Euler substitution with roots of quadratic trinomial inside square roots
@sabil81729 күн бұрын
nice solution, thank you very much
@owlsmath9 күн бұрын
Thanks! Good suggestion! :)
@slavinojunepri76489 күн бұрын
Excellent
@owlsmath9 күн бұрын
hi Slavino. thanks!
@Hussain-px3fc9 күн бұрын
When the formula doesn’t work, does that necessarily mean the integral will diverge?
@owlsmath9 күн бұрын
Yes I think for every case where the formula doesn’t work the integral diverges
@doronezri104310 күн бұрын
Crazy substitution 👏👏👏 loved the reflection formula🍻
@owlsmath9 күн бұрын
Hi Doron! Thank you 🙏 appreciate it 😀🍻🍺
@nicogehren656610 күн бұрын
Very interesting approach.
@owlsmath9 күн бұрын
Thanks Nico!
@renesperb10 күн бұрын
It is not hard to see that any integral (from 0 to inf.) with integrand a^[-x^p] * x^q ,with a >1, p > 0, q > -1 can be expressed with the Gamma function .
@owlsmath10 күн бұрын
yep agree 👍
@Aristotle-p8n11 күн бұрын
The most underrated math channel on yt
@owlsmath11 күн бұрын
awesome thanks!!! I'll take it :)
@renesperb11 күн бұрын
An elegant way to calculate this integral is to use Cauchy 's integral theorem, stating that the integral of f[z] over a closed path P in the complex plane vanishes if P does not enclose any singularities of f[z]. We write the integral as Re[1/2 ∫exp[-x^2]*exp[i x]]=1/2*Re [exp[-(x- i/2]]*exp[-1/4],and the integration is from -inf. to + inf. Take f[z] = exp[-z^2] and consider a rectangular path in C : P1 = {- N < z = x < n} ,P2 = {z = N+i*y ,(0< y < 1/2)}, P3 = {z = i/2 +x ,(N > x > -N)}, P4 = {z = - N +i *y ,( 1/2 > y > 0 ) . If we let N -> inf. ,then it easy to show that the integrals along P2 and P4 vanish. On P1 we have ∫exp[-x^2 ] =√π , on P3 we have - integral we want to calculate . Since f[z] does not enclose any singularities the sum of our remaining integrals is zero , this means that the integral = 1/2 *√π *exp[ -1/4]
@owlsmath11 күн бұрын
Thanks!
@AscendantPerfection11 күн бұрын
Beautiful 🥰🥰
@owlsmath11 күн бұрын
Thanks! 🙏
@schweinehundbullshit917611 күн бұрын
You ruin anything good in your video with your way of speaking.
@schweinehundbullshit917611 күн бұрын
Speak clearly. You mumble with your tongue and your hand.
@KentaEvans11 күн бұрын
As an engineer point of view, you could consider e=3 and proceed from there to have e^(-x^3) for an approximated result. Nice video.
@owlsmath11 күн бұрын
Makes sense! Didn’t even think about that being close to 3. Thanks!
@pedromuniz318612 күн бұрын
Not satisfied with that solution
@owlsmath12 күн бұрын
Hi Pedro. What’s up? Was there a mistake?
@MikeMagTech12 күн бұрын
@@owlsmath I went back and reviewed it and I am satisfied that it is correct.
@owlsmath11 күн бұрын
@@MikeMagTechthanks for verifying it 👍
@MikeMagTech12 күн бұрын
Great job! ; )
@owlsmath12 күн бұрын
Thanks Mike! 🙏🙏🙏
@doronezri104312 күн бұрын
Excellent 🍻
@owlsmath12 күн бұрын
Thanks Doron! Cheers! 🍻
@saidchaida543112 күн бұрын
Thanks for sharing!
@owlsmath12 күн бұрын
Thank you! 😊
@nicogehren656613 күн бұрын
Lobachvsky saved us.
@owlsmath12 күн бұрын
yep! happens quite often :) thanks
@doronezri104313 күн бұрын
Yes! Definitely Lobachevsky's 🍻
@owlsmath13 күн бұрын
Yep thanks! 🍻
@holyshit92213 күн бұрын
Лобачевский and you read this name wrong Why I insist that you should read it correctly , because others repeat your wrong pronunciation
@doronezri104313 күн бұрын
@@holyshit922 Just checked and "Nikolai Lobachevsky" is the English version in Wikipedia (and others). What would you suggest (in English)?
@holyshit92213 күн бұрын
@@doronezri1043 It would be the best if you listen carefuly their pronunciation and try to repeat it In fact we in Poland had the same phone as it is present in this name (Ł) but it was simplified and today Poles pronounce ł a little bit different that л should be pronounced If I were born at least 10 years earlier I could write more about it
@reaperskyfall669113 күн бұрын
Huff pray to God hope i don't want to face infinity problems type in my exams
@owlsmath13 күн бұрын
Hi Skyfall. Can you look at some past exams? I know some tests include these much more than others
@reaperskyfall669115 күн бұрын
We can also use many alternatives for this
@owlsmath14 күн бұрын
Good point! I think there is many ways to do this one :) thanks
@slavinojunepri764815 күн бұрын
Fantastic
@owlsmath14 күн бұрын
Thanks! 🙏🎉
@slavinojunepri764815 күн бұрын
This integral is challenging without the lnx substitution and the cancellations.