00:02
So we've got the function y equals a over x squared.
00:11
And we've got to take the derivative of it.
00:16
So that's actually the same as a x to the negative 2 power.
00:21
So that's going to give us negative 2 a x to the negative 3rd power, which is the same as negative 2a over x to the third power.
00:32
All right, so that's the slope.
00:37
But it says that this line is tangent to the graph.
00:51
So in this line, that constant doesn't even matter.
00:55
So i just want to figure out the slope.
00:58
So i'm going to add 4 y to both sides.
01:04
Since i only care about the slope, that constant didn't even matter.
01:10
Now i'm going to divide by 4.
01:15
Okay, so here the slope is a over 4.
01:19
And the first one, the slope was negative 2a.
01:23
Over x cubed oh but x is negative 2 okay i better put negative 2 in here for x x is negative 2 so that's going to be negative 8 negative 2a so that's going to be a over 4 so what we're saying is a over 4 equals a over 4 okay if a over 4 from above is the slope.
02:34
And from below, a over 4 is the slope.
02:39
Then the answer would be every value of a...