00:01
Number 46, given the field x, y, z over x squared plus y, squared, plus z squared, integrated this line over the segments from 1 .111 to 842.
00:26
Now this r of t of a line, they all start with 1.
00:35
It's going to 8 minus 1 is 7 t.
00:38
This is 4 minus 1 is 3t, 2 minus 1 is 1t.
00:42
That's r of t.
00:44
R prime of t is 7 comma 3 comma 1.
00:53
Okay, now this is x, this is y, this is z.
00:59
Plug all that into here when we write out our line and a grull after our prime dt, integral from 0 to 1, 1 plus 7t, 1 plus 3t, 1 plus t, over 1 plus 7t squared plus 1 plus 7t squared, dot that with 7, 3, 3, comma, 1, d t, d t.
01:37
All right, doing a little bit of algebra.
01:42
When we dot these two together and add them, we get 11 plus 59t over 1 plus 7t squared plus 1 plus 3t squared plus 1 plus t squared plus 2 squared now again, more algebra.
02:08
Just simplify the bottom.
02:13
We get 59t squared plus 22t plus 3dt...