00:01
So in this question, they give us this data, and they say use the trapezoidal rule to estimate the integral from x equals 1 .8 to x equals 3 .4 using a calculator.
00:13
So the first thing to notice is be careful.
00:16
You're only estimating the integral from 1 .8 to 3 .4, so the information outside that interval is irrelevant.
00:25
You may remember that if you have the integral from a to b of f of x, dx, that this is approximately equal to b minus a over 2n times the quantity of f of a plus twice f of the first interior x value, f of x1, plus two times f of x2, that's the second interior x value.
00:54
And we keep going in this fashion.
00:58
All the interior x values, there are function value.
01:02
Get doubled plus f of b and so what do we have this time well i've got 3 .4 minus 1 .8 over two times how many intervals do i have well i've got one two three four five six seven eight so my n is eight times i've got 6 .050 plus two times seven point 389 plus two times seven point three eight plus two times 9 .025 plus 2 times 11 .023 plus 2 times 13 .464 plus 2 times 16 .445 plus 2 times 20 .086 plus 2 times 24 .33.
02:08
And then just one of the 29 .964...