Calculus Help

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.undetected

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Every time I try to find a video that explains indefinite integration of natural logarithms, it always uses u substitution. Does anyone know where I could find a video explaining another way to do so, without u sub. I can't seem to find any.
 
Fuck I didn't know there was another way to do it. All I remember is the brown calc method and it used udu substitution...good luck. Honestly I am glad I am done with that shit. Never have used it damn it!
 
My teacher showed us another way to do it, but I forgot the name of the method, it was easier than u sub, but apparently nobody uses it because it isnt on youtube at all. Which may mean my teacher was lying
 
I assume your teacher is specifying that you need another method? I'd try to help but idk what to even search. I learned usub and I assumed that was it.
 
The only other common method for a log or natural log I can think of is integration by parts. That is where you use the equation integral(U*dv)=U*V-integral(V*du).
 
you can do this one with integration by parts, I remember doing it that way a few months ago but I forgot how I did it. It was something with setting one of the parts dx to = dv or du...
 
int (ln(ax) dx) The integral of ln(ax)u=ln(ax) dv=dx Set U equal to ln(ax) and dv equal to dx

du= (a/x) dx v=x Derive u and integrate dv to get du and v

int (ln(ax) dx) = uv - int (v du) Equation for integration by parts

int (ln(ax) dx) = (ln(ax)) * x - int( x * (a/x) dx) Sub u, v and du into the equation

==x * ln(ax) - x + C Solve

 
Yuck, I hated dong integration by parts and u substitutions. Just know that if you end up moving on to higher level math you will never have to do that kind of stuff by hand. Maple will be your savior.
 
really?

I have to do that often still. although I never actually write down what u is or what f & g are, I just kinda do it all in one step. I guess it depends on what type of higher level math you are doing?
 
i skimmed the thread so i dunno if someone answered you but are you asking because you need another method or just because you want another one? because its really simple once you crack it and you'll be able to do loads of different integrations without even thinking about them. i think someone posted the khan academy video, which is great. they basically taught me the most recent maths course i did this year at university
 
If your not doing u-sub's you need to to integration by parts. I remember it by saying ultraviolet voodoo.

integral of (u*dv)= u*v-integral of (v*du)
 
I just posted that without really remembering how to do it. But here it can walk you through:

u=ln(x)

dv= dx

v= x

du=1/x dx

integral(u dv) = u*v -integral (v*du)

=ln(x)*x-integral(x*1/x*dx)

=ln(x)*x-integral(dx)

=x*(ln(x)-1)
 
integration by parts literally sucks, especially when you have to use it like six times on a test. smh. calcudie.
 
well if you want to understand anything about nature you gotta learn that shit. and differential equations. and linear algebra. and complex analysis. maybe at least a little algebra and geometry as well.
 
YOU-DUN-GOOFED-INCEPTION.png
 
Sorry, when I was in college I spent my time doing other things than nerding out over calculus and making troll threads about veganism on ns.

Who sucks now?
 
first year uni I went skiing every week, partied at least three nights a week and did not attend class at all.

you still suck.
 
I consider myself terrible at math. Like really bad. I got C's and D's in it all through highschool. Integration by parts is easy.
 
Then second year at uni you moved to spray painting McDonald's signs with your douchebag friends and then begging mods to delete the thread you made about it cause you got scared?

Haaaaaaaaaaaaaaaaaaaaaa
 
nope. second year I was still skiing and partying a ton. face it. you are just an idot. what major are you? probably fucking business or something stupid haha.
 
honestly you guys point out chickens attempts to piss you off but then you fall for his shit time and time again it's classic
 
and in that time i've seen people get cranky multiple times

oh and i forgot how people can't look at the forums without an account..o wait
 
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