Need criticisms and comments on my video - C2 Integration

other than the handwriting it's good but i think it needs to be shortened a bit
oh yes you should use a ruler lol

no problem keep it up im sure that ill be using your guides in c3 and 4 will need the help then

yeah i am on my first year, I've never heard of that website before ill check it out, and yeah we/I need videos like this from a students perspective

You seem to hesitate a lot when you speak: "emm", "so basically", etc.... You need to sound more self-confident when you speak :P

And also, when you wrote the little box with $\int x dx$, it really should read $\int x^n dx$ hehe

They're pretty good. There are a few problems though (the last of which is probably the most major of the lot)

- You wrote $\displaystyle \int x\, dx = \dfrac{1}{n+1}x^{n+1}$... this is just wrong

- You spent a lot of time talking about the constant of integration and proceeded to write $\displaystyle \int f'(x)\, dx = f(x)$

- I'm a bit uneasy about "x³ graph" -- to me that means "the graph of y=x³", but it's fairly obvious what you mean (i.e. a cubic graph) so I'll let you off

- In the second video, you seem to be saying that a cubic graph with roots at 2,5,7 and a y-intercept at -10 is given by $y=x^3-3x^2+2x-10$; you got the y-intercept right, but not the roots. This has led to quite a bad mistake, because the cubic you wrote has a root between 2 and 5 (at ~3.31), so the integral evaluated directly between 2 and 5 doesn't tell you the area under the curve -- instead it tells you the area under the curve between 3.31 and 5, minus the area above the curve between 2 and 3.31.

On your first point, im confused, is it because i didnt put the + C? didnt mention n =/= -1 either

and on your last point, i completely made up the graph, and when i put it in my graph calculator, it looked horrible so yeah my bad, atleast i wasnt wrong

Constants aside, it's because $\displaystyle \int x\, dx = \dfrac{x^2}{2}\ (+C)$. You should have written $\displaystyle \int x^n\, dx$ on the LHS instead. I mean, it's fairly clear from the context for someone who's studied integration before, but if you've not studied integration then it's not clear at all.

The only real reason why I'm being so nitpicky is because people tend to copy what they're taught, whether it's by a teacher or just in an instructional video. If someone goes for a while using bad habits without questioning their accuracy, it can cost whole grades when it comes to exams.



For future reference it's a better idea to think up examples before you make the video and make sure they're accurate. It's good that you can just come up with examples on the spot, but not if you get caught out on subtleties (like here).

"integration in a nutshell"

make it shorter, it will make things easier, no need to go too long on such a simple topic. In fact this can have negative affects on ones learning.

Look at livemaths.co.uk for example, the man is quick at explaining and understanding is easier, he understands the viewers needs and gets it does and over with, and then you can swiftly move on to the next topic, whereas I'd feel tired after 12 or so minutes on something so simple

rule wasnt explicit.

He wasn't referring to the 'rule' not being explicit but rather the fact that you integrated the wrong thing. That's the integral of $x^n$, not $\displaystyle \int x dx$.

All-in-all, not a bad try. The idea of it flowing natural is good but I think have some idea of the structure beforehand will be beneficial.

ok yeah i just followed on from the example
less stuttering, and an example that actually works is needed
as soon as i saw your comment i was like 'oh no he's going to rip me to shreds' but im glad you didn't

Yeah, it's not a major problem. At this point, I would have been clutching for some excuse like "it was a typo, the n was supposed to be there ".

Really? I didn't know I had a reputation for being a harsh critic.

Hello!

Using a tablet and some software i have made a video that just explains basic C2 Integration, and i have made it to firstly help my understanding, and to help others, it's a fairly easy C2 topic which is why i chose it

MY HANDWRITING SUCKS - i know that im just trying to get used to it all

part1 http://www.youtube.com/watch?v=fJDs0Z03bz4
part2 http://www.youtube.com/watch?v=wf4og5guUHk

criticism + comments needed!