JJHanna
JJHanna
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Laplace Transform of 3t^4 - 2t^2 - 1
Find the Laplace Transform of the function 3t^4 - 2t^2 - 1.
🔗Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html
I hope you learned and understood the Differential Equations problem (Evaluating Laplace Transforms) a little better. Feel free to ask me any questions or give me suggestions in the comments below. If you enjoyed the video, please give it a thumbs up. Thanks!
Separable Equations, Integration examples, integral examples, antiderivative examples, differential equations, integral practice problems, calculus 1 practice problems, differential equations practice problems, initial value problem, approximate solution, characteristic equations, auxiliary equations, roots, root solutions, complex roots, method of undetermined coefficients, variation of parameters, Laplace transform. James Stewart Single Variable Calculus. Nagle, Saff, Snider Fundamentals of Differential Equations. In Problems 1-20, determine the Laplace transform of the given function using a provided Table and the properties of the transform. 3t^(4) - 2t^(2) - 1. 3*t^4 - 2*t^2 - 1. 3*t^(4) - 2*t^(2) - 1
This video is part of a comprehensive walkthrough of the most common problems and topics you will run into during Differential Equations. I hope you find this playlist helpful!
มุมมอง: 254

วีดีโอ

Laplace Transform of e^(-t)cos(3t) + e^(6t) - 1
มุมมอง 9621 วันที่ผ่านมา
Find the Laplace Transform of the function e^(-t)cos(3t) e^(6t) - 1. 🔗Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html I hope you learned and understood the Differential Equations problem (Evaluating Laplace Transforms) a little better. Feel free to ask me any questions or give me suggestions in the comments below. If you enjoyed the video, please...
Laplace Transform of 3t^2 - e^(2t)
มุมมอง 2062 หลายเดือนก่อน
Find the Laplace Transform of the function 3t^2 - e^2t. [VIDEO CHAPTERS] 0:00: Intro 0:37: Laplace of t^n 1:27: Laplace of e^(at) 2:10: Answer 🔗Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html I hope you learned and understood the Differential Equations problem (Evaluating Laplace Transforms) a little better. Feel free to ask me any questions or g...
Laplace Transform of t^2 + e^t sin(2t)
มุมมอง 2153 หลายเดือนก่อน
Find the Laplace Transform of the function t^2 e^t sin2t. [VIDEO CHAPTERS] 0:00: Intro 0:37: Laplace of t^n 1:26: Laplace of e^(at) * f(t) 2:26: Laplace of sin(bt) 3:36: Answer 🔗Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html I hope you learned and understood the Differential Equations problem (Evaluating Laplace Transforms) a little better. Feel...
How To Graph ALL Step Functions
มุมมอง 864 หลายเดือนก่อน
This is everything you need to know about graphing basic step functions, also known as Heaviside step functions. [VIDEO CHAPTERS] 0:00: What is u(t)? 0:26: Graphing u(t) 1:08: u(t 3) and u(t - 5) 3:02: 3*u(t) 3:34: u(-t) 4:21: u(-t 4) and u(-t - 7) 5:46: 8*u(-t - 1) 6:16: -u(t) 7:01: -u(t 3) and -u(t - 6) 7:32: -2*u(t) 7:52: -u(-t) 8:33: -u(-t - 3) and -u(-t - 7) 9:34: -6*u(-t 3) 10:06: Summary...
y'' + 4y = csc^2(2t)
มุมมอง 1514 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' 4y = csc^2(2t). In other words, find the particular solution to the given non-homogenous differential equation y'' 4y=csc^2(2t) using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Hey everyone, I ho...
y'' + 4y' + 4y = e^(-2t)ln(t)
มุมมอง 5184 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' 4y' 4y = e^(-2t)ln(t). In other words, find the particular solution to the given non-homogenous differential equation y'' 4y' 4y = e^(-2t)lnt using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Hey ...
y'' + 9y = sec^2(3t)
มุมมอง 3065 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' 9y = sec^2(3t). In other words, find the particular solution to the given non-homogenous differential equation y'' 9y = sec^2(3t) using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Blackpenredpen's...
y'' + 16y = sec(4x)
มุมมอง 3115 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' 16y = sec(4x). In other words, find the particular solution to the given non-homogenous differential equation y''(θ) 16y(θ) = sec(4θ) using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Hey everyone...
y'' + 2y' + y = e^(-t)
มุมมอง 3505 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' 2y' y = e^-t. In other words, find the particular solution to the given non-homogenous differential equation y'' 2y' y = 1/e^t using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Hey everyone, I hop...
y'' - 2y' + y = t^-1e^t
มุมมอง 3456 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' - 2y' y = t^-1e^t. In other words, find the particular solution to the given non-homogenous differential equation y'' - 2y' y = e^t/t using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Hey everyone...
y'' + y = sec(t)
มุมมอง 5338 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' y = sec(t). In other words, find the particular solution to the given non-homogenous differential equation y'' 4y = sect using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Hey everyone, I hope you ...
y'' + 4y = tan(2t)
มุมมอง 1.2K9 หลายเดือนก่อน
Determine the particular solution to the given differential equation y'' 4y = tan(2t). In other words, find the particular solution to the given non-homogenous differential equation y'' 4y = tan2t using variation of parameters with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html Hey everyone, I hope y...
Integral of (x+2)(3x^2+12x+1)^1/2 from 0 to 1
มุมมอง 3349 หลายเดือนก่อน
How to find the Integral of (x 2)(3x^2 12x 1)^1/2 from 0 to 1. In other words, Integrate the Definite Integral of (x 2)(3x^2 12x 1)^1/2 dx between 0 and 1 by U-Substitution (u-sub). Link to Calculus I playlist: th-cam.com/play/PL64VKMUnFnoZtDX2d8gsjgkuGps91f2Ed.html&si=uvz8cDZ4KbZkUypb Hey everyone, I hope you learned and understood the Calculus I problem (U-Substitution Integral) a little bett...
y'' + y = 4xcos(x)
มุมมอง 53510 หลายเดือนก่อน
Determine the particular solution to the given differential equation y''(x) y(x) = 4xcos(x). In other words, find the particular solution to the given non-homogenous differential equation y'' y = 4xcos(x) using method of undetermined coefficients with characteristic/auxiliary equations and roots. Link to Differential Equations playlist: th-cam.com/play/PL64VKMUnFnoaXbANDYY03nklV9rkugpUl.html He...
y'' - 5y' + 6y = xe^x
มุมมอง 1.6K10 หลายเดือนก่อน
y'' - 5y' 6y = xe^x
2z'' + z = 9e^(2t)
มุมมอง 34310 หลายเดือนก่อน
2z'' z = 9e^(2t)
y'' - y' + 9y = 3sin(3t)
มุมมอง 1K10 หลายเดือนก่อน
y'' - y' 9y = 3sin(3t)
2x' + x = 3t^2
มุมมอง 27010 หลายเดือนก่อน
2x' x = 3t^2
y''(x) + y(x) = 2^x
มุมมอง 29710 หลายเดือนก่อน
y''(x) y(x) = 2^x
y'' + 2y' - y = 10
มุมมอง 1.3K10 หลายเดือนก่อน
y'' 2y' - y = 10
y'' + 3y = -9
มุมมอง 2.1K10 หลายเดือนก่อน
y'' 3y = -9
Converting a Riemann Sum to a Definite Integral
มุมมอง 74010 หลายเดือนก่อน
Converting a Riemann Sum to a Definite Integral
4y'' - 4y' + 26y = 0
มุมมอง 48611 หลายเดือนก่อน
4y'' - 4y' 26y = 0
4y'' + 4y' + 6y = 0
มุมมอง 1.5K11 หลายเดือนก่อน
4y'' 4y' 6y = 0
w'' + 4w' + 6w = 0
มุมมอง 9311 หลายเดือนก่อน
w'' 4w' 6w = 0
z'' - 6z' + 10z = 0
มุมมอง 26111 หลายเดือนก่อน
z'' - 6z' 10z = 0
y'' + y = 0
มุมมอง 4.3K11 หลายเดือนก่อน
y'' y = 0
4y'' + 4y' + 7y = 0
มุมมอง 68411 หลายเดือนก่อน
4y'' 4y' 7y = 0
y'' - y' - 11y = 0
มุมมอง 37811 หลายเดือนก่อน
y'' - y' - 11y = 0

ความคิดเห็น

  • @ray_leigh00
    @ray_leigh00 5 วันที่ผ่านมา

    you saved me thanks 💙

  • @chavezyhojan1881
    @chavezyhojan1881 13 วันที่ผ่านมา

    I appreciate the video you make, I'm watching you from Peru

  • @abbeyjane9475
    @abbeyjane9475 19 วันที่ผ่านมา

    Lifesaver!

  • @Daysleaf
    @Daysleaf 24 วันที่ผ่านมา

    Much appreciated for the video , i have one question though , if we had a load resistor would the formula for the voltage gain change ?

    • @JJHanna
      @JJHanna 5 วันที่ผ่านมา

      No problem! And yes, a load resistor would change the overall gain of the amplifier circuit. You basically take Rout and put it in parallel to RL. I have another example here where I include it in the gain calculation: th-cam.com/video/V8VCzWV8Kgo/w-d-xo.html

  • @marcol6363
    @marcol6363 25 วันที่ผ่านมา

    Where would you put in any given initial conditions?

    • @JJHanna
      @JJHanna 15 วันที่ผ่านมา

      So if you have y(0) = 2 and y'(0) = 1 for example, you take the final solution ygen, and plug t = 0 and have the LHS = 2. After doing so, you'll get C1 = 2. Then, take the derivative for ygen', and plug t = 0 and set the LHS = 1. After doing so, you'll get C2 = 3. Now, using C1 = 2 & C2 = 3, you can plug those constants into ygen = 2e^-t + 3te^-t + 1/2 * t^2 * e^-t

  • @alimohammedhadi4191
    @alimohammedhadi4191 หลายเดือนก่อน

    Wow thanx alot

  • @user-um4qk9du9h
    @user-um4qk9du9h หลายเดือนก่อน

    Wow this was an amazing explanation. Super concise and showing every part

  • @ey3796
    @ey3796 หลายเดือนก่อน

    Thank you so much! I just have one doubt, does all collector current flow through Rc and straight to collector? Do we not need to include the load resistor? Please help.

    • @JJHanna
      @JJHanna 5 วันที่ผ่านมา

      Given that there's a DC blocking capacitor in between RL and Rc, under DC conditions, the capacitor is open. This means that current flows straight from 20V through Rc and into the collector. So you are correct in your assumption. Due to this, the load resistor has no effect on the collector current Ic, which we found to be 4.125 mA.

  • @simarjotkour
    @simarjotkour หลายเดือนก่อน

    what should be done if in case of S2 we are given Z1 = 0.51<-33.7ohm and in placeof S3 we are given Z2 = 1.568<23.84ohm?

  • @IronEspirit
    @IronEspirit หลายเดือนก่อน

    WOW! THANK YOU VERY MUCH BUDDY! YOU SAVED ME!

  • @zi0501
    @zi0501 หลายเดือนก่อน

    thanks

  • @CricSpinOfficial
    @CricSpinOfficial 2 หลายเดือนก่อน

    yes the answer the π/ 2 👍 Thanks

  • @Ralon.
    @Ralon. 2 หลายเดือนก่อน

    By walli formula

  • @nicholasleclair995
    @nicholasleclair995 2 หลายเดือนก่อน

    Oops I tootied

  • @chuffalufagis5534
    @chuffalufagis5534 2 หลายเดือนก่อน

    This was so helpful thank you

  • @AnmolLahot
    @AnmolLahot 2 หลายเดือนก่อน

    You forget rubidium hydroxide,Mg(OH)2,

    • @JJHanna
      @JJHanna 2 หลายเดือนก่อน

      I wouldn't consider it common enough of a base to put it on this list, but you're more than welcome to include it!

  • @chuffalufagis5534
    @chuffalufagis5534 3 หลายเดือนก่อน

    This was so helpful thank you!

  • @sandeepkumargupta2458
    @sandeepkumargupta2458 3 หลายเดือนก่อน

    Thanks

  • @meteoktem
    @meteoktem 3 หลายเดือนก่อน

    THANK YOU SO MUCH

  • @chuffalufagis5534
    @chuffalufagis5534 3 หลายเดือนก่อน

    This was so helpful thank you!!!

    • @JJHanna
      @JJHanna 3 หลายเดือนก่อน

      Np bb

  • @Anushka-ss4og
    @Anushka-ss4og 4 หลายเดือนก่อน

    Since we have the identity for cosx= sinx, shouldn't we have to assume cosx as some variable "t" and integrate it first. Or is there a direct identity for cos(2x)?

    • @JJHanna
      @JJHanna 4 หลายเดือนก่อน

      Could you elaborate on the identity that you mentioned where cosx = sinx? Do you mean via phase shift? Because otherwise there's no situation that I could think of in which they're directly equivalent. Honestly I don't think substitution is needed, since the power reduction (half angle identity) is the most straightforward way to approach this problem. As a side note, the integral of cos(ax) = 1/a * sin(ax). Since the coefficient was already = 2 in 2cos(2x), the integral would be 2/2 * sin(2x), reducing to sin(2x).

  • @sarahvictoriart
    @sarahvictoriart 4 หลายเดือนก่อน

    BLESS YOU!!!!

  • @1sus1000
    @1sus1000 4 หลายเดือนก่อน

    Resident evil

  • @indrajeetshinghrana9103
    @indrajeetshinghrana9103 4 หลายเดือนก่อน

    Thanks bhayo

  • @thanhvinhnguyen6024
    @thanhvinhnguyen6024 4 หลายเดือนก่อน

    Wait is that really mosfet, i thought it was JFET, a little confuse about the Ig, hope you reply!!

    • @JJHanna
      @JJHanna 4 หลายเดือนก่อน

      I can see why you're confused. The schematic symbol for a MOSFET has a disconnected line for the gate (G). On the other hand, for a JFET, the line for the gate (G) is connected directly to the Drain (D) and Source (S). I've attached a link explaining more: www.electricaltechnology.org/2021/04/difference-jfet-mosfet.html By Ig, do you mean gate current? If so, Ig = 0 is because the gate terminal is isolated from the substrate by a dielectric medium. This is of course under ideal conditions. Realistically, there's always a minuscule amount of leakage current going through. But we're talking about pA to nA range, so we could usually neglect that. Does that make sense?

  • @OgelekaEmmanuel-wl5ei
    @OgelekaEmmanuel-wl5ei 4 หลายเดือนก่อน

    Find the solution of the equation that satisfies the solution Y(0) = 1, y¹(0) = 7

    • @JJHanna
      @JJHanna 4 หลายเดือนก่อน

      Starting from the general solution Yh = C1*e^(-3t) + C2*t*e^(-3t), we have an initial value problem (IVP) given the conditions y(0) = 1, and y'(0) = 7. Start with simply plugging in y(0) = 1 into Yh. It becomes 1 = C1*e^(-3*0) + C2*(0)*e^(-3*0) since y = 1, t = 0. Simplifying, 1 = C1 + 0, then 1 = C1. We can conclude from the first condition that C1 = 1. Now, to plug in y'(0) = 7, we have to take the derivative of Yh. Yh' becomes -3*C1*e^(-3t) + C2*e^(-3t) + (C2*t)(-3*e^(-3t)) using chain rule on the second term. Plugging in y'(0) = 7 with y' = 7, t = 0 -> 7 = -3*C1*e^(-3*0) + C2*e^(-3*0) - 3*C2*0*e^(-3*0). Simplifying and plugging in C1 = 1 from the previous equation, 7 = -3*1 + C2. Then C2 = 7 + 3 = 10. Therefore C2 = 10. Plugging in C1 = 1 and C2 = 10 into the original Yh equation -> Yh = e^(-3t) + 10t*e^(-3t)

  • @EpheSune
    @EpheSune 4 หลายเดือนก่อน

    Very impressive. I can memories it

  • @randhyLeksu7288
    @randhyLeksu7288 4 หลายเดือนก่อน

    is laplace applicable for this

    • @JJHanna
      @JJHanna 4 หลายเดือนก่อน

      Yes, but that requires advanced techniques. This is the most straightforward way to evaluate this problem in my opinion.

  • @felipefred1279
    @felipefred1279 4 หลายเดือนก่อน

    I really like differential equations. You have exercises with laplace transform and change of parameters?

    • @JJHanna
      @JJHanna 4 หลายเดือนก่อน

      Yes my past 8 videos or so are variation of parameters. Laplace will be my next series!

  • @felipefred1279
    @felipefred1279 4 หลายเดือนก่อน

    Amazing work

    • @JJHanna
      @JJHanna 4 หลายเดือนก่อน

      Thank you

  • @olivertopa
    @olivertopa 4 หลายเดือนก่อน

  • @AmbouR
    @AmbouR 5 หลายเดือนก่อน

    which IDE are you using?

    • @JJHanna
      @JJHanna 5 หลายเดือนก่อน

      jGRASP

    • @AmbouR
      @AmbouR 3 หลายเดือนก่อน

      @@JJHanna thankyou

  • @adastra123
    @adastra123 5 หลายเดือนก่อน

    Thank you so much. Subscribed.

  • @RobiTagore-yn6sp
    @RobiTagore-yn6sp 5 หลายเดือนก่อน

    A blessing for the weak mesmerizers like me, who only understands but cant remember!

  • @justincatagua6067
    @justincatagua6067 5 หลายเดือนก่อน

    I have one question, as a homogenous equation the input is e^alpha*t multiplied by (c1cosbeta*t + c2sinbeta*t) where alpha is one and beta is zero which wouldn't it j be c1e^t since c2 cancels out with sine

    • @JJHanna
      @JJHanna 5 หลายเดือนก่อน

      You're qualifying assumption is correct. Since Beta is zero (no imaginary component) the sine term cancels out. And Alpha = 1 (real component), the Ce^rt term remains. However, in this particular case, there are repeated roots. Therefore the general form must be C1e^(r1*t) + C2 * t * e^(r2*t). It would only ever be C1e^r*t if there was *one* *real* *root.* But again, we have two repeated ones. Does that make sense?

  • @ahmed_fouad1199
    @ahmed_fouad1199 5 หลายเดือนก่อน

    Why in Rout1 we didn't count that it is vth2 is parallel to rc1 and ro

    • @JJHanna
      @JJHanna 5 หลายเดือนก่อน

      I separated each stage so that I can take each external voltage gain into account during the final AC analysis gain calculation starting at 24:20.

  • @СардорЗаитов-н7с
    @СардорЗаитов-н7с 5 หลายเดือนก่อน

    Қалихан Арай көшіріп жатыр

    • @JJHanna
      @JJHanna 5 หลายเดือนก่อน

      ДДСҰ?

  • @Panji_Ryan
    @Panji_Ryan 5 หลายเดือนก่อน

    Thank you!!, you just saved a day of headache

  • @BENJAMINFELDMAN-ke3qt
    @BENJAMINFELDMAN-ke3qt 5 หลายเดือนก่อน

    Hey, the derivative of 1-cost is not sint. Would it not be 1+sint??

    • @JJHanna
      @JJHanna 5 หลายเดือนก่อน

      Derivative of -cost = sint. 1 is a constant so it turns to zero.

  • @doictbarguna2266
    @doictbarguna2266 5 หลายเดือนก่อน

    ∫_(0)_(π)sin²(x)dx=∫_(0)_(π)(1-cos(2x))/dx

    • @JJHanna
      @JJHanna 5 หลายเดือนก่อน

      You're forgetting the 1/2 coefficient but true!

    • @doictbarguna2266
      @doictbarguna2266 5 หลายเดือนก่อน

      @@JJHannathanks

  • @Shabnam71237
    @Shabnam71237 5 หลายเดือนก่อน

    Thank u❤❤❤❤❤❤

  • @ksteph5566
    @ksteph5566 6 หลายเดือนก่อน

    Why doesn’t the c get times by 2

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      You could move C around like that if you want. If it's multiplied by any constant it will always stay as C. I just left it in the log so that there's only 1 term as an answer.

  • @mrcrabs5782
    @mrcrabs5782 6 หลายเดือนก่อน

    can this equation be consider seperable? to solve?

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      For this specific problem, the x and y terms can't be completely separated from each other such that x is on one side being multiplied by dy/dx and y on the other. So no, this is not a separable equation.

  • @sharequsman596
    @sharequsman596 6 หลายเดือนก่อน

    Hey idk if this is a dumb question but why couldn't you integrate cos^4thetha by taking cos as the operator since it has a power of 4 on it

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      I understand what you mean. The property where you can add 1 to the exponential numerator and put it over the denominator when integrating only applies to simple polynomial functions. Every other expression requires a special sort of identity or trick as I've shown in the video. So no, you can't just say cos^5(x)/5 as the answer.

    • @sharequsman596
      @sharequsman596 6 หลายเดือนก่อน

      @@JJHanna AHH that explains why I was confused.You could do so if it was cos^2thetha tho right?

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      only if it's cos(constant * x). Then you could use u-sub to make it = 1/constant * sin(constant * x). No matter what, you can't linearly add powers to the trig terms.

    • @sharequsman596
      @sharequsman596 6 หลายเดือนก่อน

      @@JJHanna AHH thnx man you earned a sub

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      @@sharequsman596 thanks so much! If you have any other question let me know.

  • @HamzaKhan-jl7jb
    @HamzaKhan-jl7jb 6 หลายเดือนก่อน

    bro its just formulas\

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      Yup!

  • @nicholasleclair995
    @nicholasleclair995 6 หลายเดือนก่อน

    Bro needs to come up with better thumbnails

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      Bro needs to get off TikTok with that 0 attention span

  • @chuffalufagis5534
    @chuffalufagis5534 6 หลายเดือนก่อน

    This has been so helpful thank you so much ❤

    • @JJHanna
      @JJHanna 6 หลายเดือนก่อน

      ❤️❤️❤️

  • @mateusdonr
    @mateusdonr 6 หลายเดือนก่อน

    Cara, você salvou muito agora.

  • @AbhishekSharma-wp1wx
    @AbhishekSharma-wp1wx 6 หลายเดือนก่อน

    Nice explanation It was really helpful😊