Partial derivatives of vector fields, component by component
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- เผยแพร่เมื่อ 23 พ.ค. 2016
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Here we step through each partial derivative of each component in a vector field, and understand what each means geometrically. - แนวปฏิบัติและการใช้ชีวิต
Small correction: The partial derivative of Q in respect to x (dQ / dx) at the selected point (2,0) is actually equal to "-4" and not "-2" as shown .
i was just going to write that
Correct but we have to compromise that, is it not?
3:40
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thank you. fantastic tutorial!
@3:38 Should dQ/dx=-4 instead of -2?
hmm , let choose an arbitrary (x,y) in the first quadrant, now look at x-component (i call it f_1 which is xy),
we have partial derivative d(f_1)/dx = y > 0 -> means a little nudge in x direction cause f1 increase, but i came to the graph and see that the vectors kind of shorter in x direction, they are kind of 'pointing downward'
can anybody explain it to me ? 🤨
Is there any way to have the curvature formula based on partial derivatives with two parameters?
At 6:47 isn't the y component increasing as we move towards positive y? If yes then how is partial of Q wrt y zero?
Not increasing,, but kind of remains same ... that's why it came out to be 0
If you plot it using line instead of vector fields, it will looks like a curve where point (2 , 0) is the critical point (i.e maximum value) **horizontally** of that curve
Since vertical's critical point is df/dx = 0. Then, horizontal's critical point basically means df/dy = 0
It is *decreasing* in both positive-negative y direction.
Positive y : decreasing by anti-clockwise rotation
Negative y : decreasing by clockwise rotation
I am two years late, but I think I understand it. look at what the change in y component with respect to y came to be for every point not only at a specific point. it is not a constant, but a function of y.
partial of Q wrt y is equal to 2y. but for specific points where y = 0 it gives zero (which means along the x-axis.
the function equal to 2y means that as you move towards positive for larger and larger values of y the y component of the vector v increases faster (in positive direction) whereas for negative values of y it decreases and at some point, you should notice that it reverses its direction.
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Why do these have so few views?
Yeah, KA should be getting more views.
I think it's because Khan Academy doesn't try to spread its videos on TH-cam. E.g. they NEVER ask people to like and subscribe. They are more focused on getting views from their own website. This seems like a mistake on their part; imho, they should be trying to direct people to their website from their TH-cam videos, but none of the video descriptions link back to the lesson(s) that the video is used in :/
freat video
this is the comment after 2 years