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U-substitution with definite integral 

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Example of using u-substitution to evaluate a definite integral
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11 сен 2024

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Комментарии : 96   
@warwick802
@warwick802 Год назад
For calculus 2 you basically choose to either plug back "u" and leave the bounds alone or change the bounds and leave it as u.
@GatorsCloset
@GatorsCloset 11 лет назад
This video is more complicated than it needs to be. When you substitute the "1/2x" into the integral you'll have "x/2x" the x will disappear and you'll be left with "1/2" and since it is a multiplier you just bring the one half outside of the integral. This is a lot more simple than multiplying by two and one half to keep the integral the same in order to have a "2x/2x".
@wtbgothgf
@wtbgothgf 8 лет назад
You have no idea how much you've helped me out this semester. I'll do my best to pay it forward!
@gracepackard6838
@gracepackard6838 8 лет назад
Sal, you are the light of my life.
@HotPepperLala
@HotPepperLala 11 лет назад
Sal sounds so organized and prepared now. But for some reason I like the old Sal videos lol
@Heirophanteye
@Heirophanteye 11 лет назад
Sorry, I have a Masters in both Business Admin and Accounting. I took AP Calculus AB and BC in High School but didn't have to in college. I am always looking to improve myself so I am trying to learn new things; such as refreshment on calculus and physics topics.
@Thedreamshaperabc
@Thedreamshaperabc 11 лет назад
Well often this would be only a very small part of a larger application, not all things can by it self be directly applied. I truly get how we want things to have a direct application, but sometimes one simply needs to take a leap of faith and try to learn the theory and realize than unless one wants to go into plumbing and construction, some times things will get abstract :)
@allieyi
@allieyi 6 лет назад
Thanks so much! I have test this morning, and I needed this!
@joelplascencia3568
@joelplascencia3568 8 лет назад
You see, I understand how to do it now, but I still don't get the purpose.
@GrimmjowJaegerjaquez
@GrimmjowJaegerjaquez 6 лет назад
Joel Plascencia it's been two years, do you get the purpose yet?
@thebanish3r355
@thebanish3r355 4 года назад
3?
@jamesrich3161
@jamesrich3161 4 года назад
3 years later and your question still stands buddy
@mohammedhoque7671
@mohammedhoque7671 4 года назад
4 years still no purpose??
@joelplascencia3568
@joelplascencia3568 4 года назад
@@mohammedhoque7671 I posted this during my senior year of high school. I'm now a fourth year of college, and I learned the purpose about 2 years ago
@muffemod
@muffemod 6 лет назад
Warning: In order to use substitution, the intergrand must contain the derivative of the inside function, to within a constant factor.
@pram5532
@pram5532 3 года назад
tf is an intergrand
@JasonVaysberg
@JasonVaysberg 2 года назад
@@pram5532 the function that is going to be integrated. xsin(x^2) is the integrand in this case.
@NewWesternFront
@NewWesternFront Год назад
@@pram5532 it's a form of ligma
@jonathanalonso6492
@jonathanalonso6492 Год назад
@@pram5532 An integrand is the result from basically converting an integral back into a higher-order function. An integral is the same as getting the derivative of whatever higher-order function you started off with. For example: an integral, like 2x, is what you get after differentiating x^2. They are opposites of each other.
@Heirophanteye
@Heirophanteye 11 лет назад
I suppose everyone is entitled to their opinion; which is why I expressed mine. I like that integral calculus has uses. I was simply suggesting that before or perhaps during the explanation of the technique being taught that use of technique in a real world example would be helpful. If I hand you a tool and fail to teach you what it can be used for, I am relying upon you to figure out how to use it. Sure, eventually I may figure it out but it's faster to teach me up front what it is used for.
@melikyuksel4527
@melikyuksel4527 9 лет назад
I love you Sal, you did in 5 minutes what my textbook did in 30.
@josuequintero-td5gh
@josuequintero-td5gh 7 месяцев назад
Textbooks aren't bound by time
@inglesyeses
@inglesyeses 11 лет назад
hi. i have a feeling you should write the 'd' properly, otherwise people could get confused later with partial differential equations where the d's are written more curly like in your vid... just a thought.
@humiraarroyo
@humiraarroyo 6 лет назад
thank you! so so helpful and straightforward!
@DRJACOBB
@DRJACOBB 11 лет назад
I was an award winning teacher--in the fourth largest district in the United States, I harnessed the power of technology to take my students to places they have never been! I provided implementation ideas to my school and the children really benefitted. More power to you! By the way, "Giving Our Students the World" is my motto and it is now the motto for ~ 400,000 students. So, yes, I AM a caring teacher--that's my philosophy.
@agent-sz2qj
@agent-sz2qj 8 лет назад
substitution was my nightmare, but not anymore thanks to you
@EytanWallace
@EytanWallace 11 лет назад
Yes. As long as you don't accidentally take the antiderivative in terms of U with the X bounds.
@likesomehero
@likesomehero 11 лет назад
You are the reason why education in America needs reform
@sarahholland5980
@sarahholland5980 6 лет назад
Completely forgot how to do u-substitution and my exam is in two weeks. Thanks Sal!
@EvilMastermind
@EvilMastermind 7 лет назад
I freaking HATE integrals. I am litteraly never going to use them in my entire life and I am forced to learn them. Plus to make things worse, every person I watch who is calculating integrals does it completely different somehow. Jus out of the blue every time...
@muffemod
@muffemod 6 лет назад
You will be faced with problems in life. You will be forced to solve them. If you can apply logic and reasoning to solve problems in mathematics, you can transfer those skills into other areas of life.
@evanmastermind
@evanmastermind 5 лет назад
@@muffemod Wrong.
@go2grave01
@go2grave01 11 лет назад
We use functions for all kinds of things(physics,computer science,astronomy).
@joose9748
@joose9748 6 лет назад
try showing an example of substitution when you cant use the u' straight on ...these are type "Oh look at that how lucky am I there is u' sitting right next to my u"...
@user-ub2dp7fp2d
@user-ub2dp7fp2d 7 лет назад
do we need to +C again in behind of result, sal??? thanks.. you enlighten the enlightenment
@zestyorangez
@zestyorangez 7 лет назад
no because the integral is definite
@MrMarkgyuro
@MrMarkgyuro 4 года назад
thank you khan! very good explanation!!
@danhassler6585
@danhassler6585 3 года назад
Great! makes it easy to understand.
@EytanWallace
@EytanWallace 11 лет назад
Can someone please briefly explain why we need to multiply by 2 and .5 in the beginning?
@zixan
@zixan 11 лет назад
what a good refresher after five years of no math class
@danielpersaud2008
@danielpersaud2008 10 лет назад
do u always always always take the new limits?
@pa800korg92
@pa800korg92 10 лет назад
AWESOME TEACHER!!!!!
@Heirophanteye
@Heirophanteye 11 лет назад
Wow. I really need to go back to college. Two master's degrees and I still don't understand the application of this math. What would I even use it for? These videos could be significantly enhanced by starting with a real-world use so that I can start integrating the knowledge by seeing it in context. Then I could understand how the components fit together. Math for math's sake is dry; even for someone who loves learning new things.
@eleftheriosgkioulekas1001
@eleftheriosgkioulekas1001 2 года назад
Mathematics IS a real world. You use substitution to do integrals. E.g. it can reduce a wide range of trigonometric integrals to rational integrals. Among other things.
@alexdrudigmail
@alexdrudigmail 11 лет назад
Would you mind stating the area of your academic studies? I mean no disrespect, I'm just appalled to realize that teachers at post-graduate level can avoid explaining the huge real world impact of basically any branch of calculus.
@MiladD25
@MiladD25 10 лет назад
At which school level did you guys first did this? high school or college?
@domestic_god
@domestic_god 11 лет назад
Is this A-Level or Degree level mathematics?
@boihi1496
@boihi1496 5 лет назад
This helps so much ty for review
@SerdnaZe
@SerdnaZe 9 лет назад
What happened to u=x^2 at the end?
@Knexfoof
@Knexfoof 11 лет назад
Saviour Sal Strikes Again! Thanks Sal :)
@Avdbz
@Avdbz 11 лет назад
obviously you haven't paid much attention during class, integrals are used to solve,max-mini equations, in fysics, for calculating the area under a curve, it s used extensively in economics alongside with derivatives.... my man if only you would take the time to have a greater look in to every practical thing around us, you would quickly realize that 90% is built upon math... so not math for math s sake is not dry. it s all around us...
@emmanuelphiri2086
@emmanuelphiri2086 7 лет назад
thanks so much SIR you saved my time
@DRJACOBB
@DRJACOBB 11 лет назад
By the way, I remember calculus, but the thing that brought me here was Nightline. The One World School book sounds like it is perfectly aligned with my philosophy--a must read for me. Great job, my friend--and I, too, have an M.B.A. but taught children out of love.
@taylorkamann21
@taylorkamann21 8 лет назад
👋🏽 Sal you're the best.
@NightSwipe17
@NightSwipe17 10 лет назад
Thank you so much, I finally understand this.
@keotshepilemandona9882
@keotshepilemandona9882 6 лет назад
THANKS KHAN ......
@FajorMuckup
@FajorMuckup 11 лет назад
I mean you just see its -cos(x^2) without substitution after a while
@dr.willisofficial8041
@dr.willisofficial8041 3 месяца назад
Thank you so much!
@zldms93
@zldms93 11 лет назад
정리진짜잘하당ㅎㅎ
@ab.bull117
@ab.bull117 2 года назад
Thakn you
@heavymetaldeath4life
@heavymetaldeath4life 11 лет назад
"Math for math's sake is dry; even for someone who loves learning new things." Pure mathematicians like G. H. Hardy would strongly disagree. Besides, integral calculus is used in areas like electromagnetism, and by extension electrical engineering.
@ricois3
@ricois3 11 лет назад
Sign of you!
@sveta89
@sveta89 11 лет назад
this is great but i could have used it five months ago ... when i needed it badly
@badboyesed
@badboyesed 11 лет назад
why there is no professor like you in my college ... my wold have bean easier :$
@odefeoberabor7597
@odefeoberabor7597 9 лет назад
Bravo ! Thanks
@kane3743
@kane3743 7 лет назад
thank you
@Schiltzy_ISU
@Schiltzy_ISU 5 лет назад
are you a god?
@peanutcookiefantacheesypan496
@peanutcookiefantacheesypan496 5 лет назад
yes
@jamesbra4410
@jamesbra4410 6 лет назад
Nobody learns when you pick the easiest example
@thoriso1000
@thoriso1000 10 лет назад
Still confused :'(
@OSMADO
@OSMADO 10 лет назад
you have to study antiderrivatives to get this... it's pretty simple once you practice it and get it through your head
@hilalbasibuyuk3459
@hilalbasibuyuk3459 Год назад
görselliği bile mükemmel
@rzxwm10
@rzxwm10 11 лет назад
calculus
@ngotuan0881
@ngotuan0881 11 лет назад
12th grade level mathematics./.
@changjin1229
@changjin1229 11 лет назад
쉽다
@tuber324
@tuber324 11 лет назад
Please tell me you're kidding. -.-
@1234airows
@1234airows 11 лет назад
algebra
@iComicE
@iComicE 11 лет назад
2nd
@eaflores93
@eaflores93 11 лет назад
9th
@wntrsldr5077
@wntrsldr5077 6 лет назад
This subject = kms
@Shihai0Tensei
@Shihai0Tensei 11 лет назад
a-level
@w2010rcdas
@w2010rcdas 11 лет назад
3rd
@tigerclaw3211
@tigerclaw3211 11 лет назад
1st
@stopdropandroll
@stopdropandroll 11 лет назад
most likely trolling lol
@badboyesed
@badboyesed 11 лет назад
my life* wold have bean easier :$
@elitesniper3211
@elitesniper3211 11 лет назад
This is BORING
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