00:01
Okay, so we want to find the values of x, which make our tangent line true.
00:06
In this case, we're parallel to our y is equal to x line.
00:11
But this means that if we take the derivative of this, we have a slope of 1.
00:17
So when we take the derivative of the term that we want, we're going to set that equal to 1.
00:23
So here we have 2x times x plus 1.
00:26
We're going to use our quotient rule, and it's minus x squared plus 1, all over x plus 1.
00:31
To the part of 2.
00:34
So we get a 2x squared plus 2x minus x squared and minus 1, all over x plus 1 to the part of 2.
00:43
This is equal to 1, right? okay, so let's multiply x plus 1 to the power of 2 on both sides.
00:51
So we get 2x squared plus 2x minus x squared...