Examples of using Line integral in English and their translations into Thai
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Colloquial
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Ecclesiastic
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Ecclesiastic
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Computer
And when I say that, I mean that let's say I were to take this line integral along the path c of f dot d r, and let's say my path looks like this.
So our position vector function-- we always need one of those to do a line integral or a vector line integral--r of t is going to be equal to x of t times i plus y of t times j 4t going between a and b.
And then if f is conservative, and this is the whole reason we want to do it, that means that any closed loop, any line integral over a closed curve of f is going to be equal to 0 and we would be done.
Line integrals over vector fields, the direction matters.
And this is really the same idea we do with… the line integrals.
It's completely analogous to… what we did in the two-dimensional case… with the line integrals.
Let's see if we can use our knowledge of Green's theorem to solve some actual line integrals.
The line integral over the path of the curve c of p dot dr.
So I think that was you know, a pretty neat application of the line integral.
It's not clear to me that this is some type of even a vector line integral.
So this integral can be rewritten as the line integral, the curve c-- actually let me do it over down here.
So let's do all of that and actually calculate this line integral and figure out the work done by this field.
It only had an x-component, the vector field, but we have just simplified this line integral to being equivalent to-- maybe.
Now we learned several videos ago that if we're dealing with a line integral of a vector field-- not a scalar field.
In the next video, I'm going to see what happens when we evaluate this line integral, f of x ds, versus this.
If we want to find this line integral, this line integral is going to be the same thing as the integral-- let me pick a nice, soothing color.
Now let's see if there's any way that we can solve this line integral without having to resort to a third parameter, t.
But if you look at it this way, this line integral can be rewritten as being equal to the integral, let's just do c2 first.
The line, if we have a potential in a region, and we may be everywhere, then the line integral between any two points is independent of the path.
But this is what I want you to understand right now, because we're going to be able to use this in the future, when we do the line integral over vector-valued functions.