00:01
Okay, here is my curve y equals 2 over x.
00:04
I want to work out the slope of the curve at the point 4, 0 .5.
00:09
That means find d .y by dx.
00:12
Well, first of all, write y as 2, x to the minus 1.
00:17
Just rearrange it like that, same thing.
00:20
And then i can work out dy by dx.
00:23
Negative 1 times 2 is minus 2, minus 1, minus 1, minus 1 is minus 2.
00:29
And that is minus 2 over x squared.
00:36
So when x equals 4, as in this case here, the slope, or do y by d x, is minus 2 over 4 squared...