00:01
Here, we're given the equation x plus y squared minus 1 minus y is equal to 1.
00:06
And we're looking at the point x equals 1.
00:08
We want to find the equation of all tangent lines to this curve.
00:12
So the first step is to find which points do we have? so if x is equal to 1, what is y? well, we have 1 comma 0, that's one point.
00:20
And we also have 1 comma 1.
00:23
That's another value.
00:25
So these are the two points we want to look at.
00:28
Now i'm going to use the equation y equals y -not plus m.
00:33
Times x minus x not.
00:36
X not and y not are given.
00:37
Say if i use that equation, x not is one, y not is zero.
00:41
Now m is going to be the derivative at that point...