Hello, im a little bit confused, cause when we choose for the u (integration by parts), there is a rule that u need to be chosen by Exponential first then only Trigonometry, but at here the u is trigonometry first, how is that happen?
I wouldn’t say that’s a hard rule that always has to be followed. It’s just a guide. Also trig functions actually can be written in terms of exponential so they are almost the same.
It’s just preference. I try to use tabular with polys. Not everyone is super familiar with the method so doing it for sine and cosine with exponential is less familiar to people.
It’s a method of integrating by parts multiple times. You create a column for u and a column for dv. If you have a polynomial multiplied by trig or exponential then you put it in the u column and differentiate it down to zero. You stick the other function in the dv column and integrate it down the same level. Then multiply the terms on the diagonals. Google will probably have some better explanations. I may try to make a video on it soon. I’ll let you know if I do.
Great! but didn't show the formula for integration maybe for someone can be not easy to understand. Anyway like from me! Keep going, Jonathan! Don't kill people because of your dog....
you also can use euler form of cos(t)=1/2(e^jt + e^-jt) as j is the imaginary component(sqrt(-1))
thanks guy, needed this
You're welcome! I'm always happy to have helped!
Thank you so much
You made me to understand that very easily :)
Awesome! I’m glad this was helpful!
Thank you for the video. You have an excellent voice for this.
Thank you for your support!
Thank you sooooooooooooooo much!
Glad to help!
1:33 Why cant we take u as e^(-st)
The best video
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Hi, i'm confused when you went from k^2/s^2 to (1+k^2/s^2) it starts at 5:36
I moved the -k^2/s^2 L{cos(kt)} to the left hand side and factored out L{cos(kt)}.
great video! Thanks for the help (:
Thanks! Hope it helped. Thanks for watching alexandra!
what is cosine infinity? why do we assume that it is zero?
2:43
It’s not the cosine part that is zero; it is the exponential at infinity that is zero.
Thank you SO much!!
Always happy to help!
Is there some rule, cus -1/(s)*e^(-s*0)*cos(0*w)=MINUS1/s not 1/s
2:23
It's the lower bound of integration so we're already subtracting.
Thanks for this video!
You're very welcome! I'm glad it was helpful!
Hello, im a little bit confused, cause when we choose for the u (integration by parts), there is a rule that u need to be chosen by Exponential first then only Trigonometry, but at here the u is trigonometry first, how is that happen?
I wouldn’t say that’s a hard rule that always has to be followed. It’s just a guide.
Also trig functions actually can be written in terms of exponential so they are almost the same.
It’s not a rule, just a guide.
very helpful video, thanks
Always glad to help! Thanks for watching!
very nice and helpful video
Thanks! Always happy to help! Thanks for watching!
Thanks man
No problem!
thanks sir
Always happy to know this has helped! Thanks for watching!
Why don't you use the tabular method to find the integral?
It’s just preference. I try to use tabular with polys. Not everyone is super familiar with the method so doing it for sine and cosine with exponential is less familiar to people.
what's the tabular method?
It’s a method of integrating by parts multiple times. You create a column for u and a column for dv.
If you have a polynomial multiplied by trig or exponential then you put it in the u column and differentiate it down to zero. You stick the other function in the dv column and integrate it down the same level.
Then multiply the terms on the diagonals.
Google will probably have some better explanations. I may try to make a video on it soon. I’ll let you know if I do.
Very helpful
I’m so glad this helped! Thanks for checking it out!
Thanks
Glad this helped! Thanks for checking it out!
tks
Glad I could help!
Great! but didn't show the formula for integration maybe for someone can be not easy to understand. Anyway like from me! Keep going, Jonathan! Don't kill people because of your dog....
Thanks for your feedback!