00:01
All right, so what i would do in this problem is just identify that this has a height of 3.
00:06
Let me write that off to the side.
00:09
And then with all the way across being 2, that means each individual piece is 1 on either side.
00:16
Let me just put point p somewhere on here, and let me just identify what's going on.
00:22
It's called this x, which means this little piece up here needs to be 3 minus x.
00:31
And what did they want? so they wanted to connect b and ap and bp and cp.
00:42
So let's figure out, i forgot which one was which now.
00:47
So a was at the top, b was over here, and c was over here.
00:52
So i need to do the pythagorean theorem to figure out what pc is, which would be one squared plus plus x squared, and then you square root that.
01:00
And that's actually going to be the same on this side.
01:03
So then the sum, i'm going to use x as my variable, is we have two of those square roots of 1 plus x squared, but then we have to add to it that 3 minus x.
01:16
And i'm setting this up like this, so then we can take the derivative.
01:22
And remember, the square root's the 1 half power.
01:25
Let me write that right here.
01:26
Here.
01:28
And i multiply the exponent by the coefficient, which brings me to 1.
01:32
And now it's to the negative 1 half power, which puts it in the denominator, times the derivative of the inside, which is 2x.
01:39
Derivative of 3 is 0.
01:40
Derivative of negative x is negative 1...