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Hi.
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Today we are going to look at the problem of writing the parametric equations for a line that passes through a point 3 negative 4 negative 1 and is parallel to the vector i plus j plus k.
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The problem doesn't ask us to draw a picture of this, but let's make a rough sketch so we can see what it is we are trying to accomplish these vectors.
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So the first is this vector i plus j plus k this is one unit in i, one unit in j, one unit in k.
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That is one place up in x, one positive in y, one positive in z.
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This is the unit vector ijk.
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And this point is at three in x, negative four in y and y and down one z.
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So what we are trying to do is draw the line that is parallel to this line, this vector, but includes this point p over here.
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So if you think about it, what we have to do is we have to take this vector, and we have to slide it down, translate it, so that it begins at p.
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And then from this p, it will continue up in one unit x, one unit y, one unit z, like this.
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The line, of course, is infinite in this direction and infinite in that direction...