00:01
Today, we'll be finding the slope of a line tangent to the curve y equals x minus x cubed at the point one zero, then we'll find the equation of that line, and finally we will look at that line on a graph.
00:12
To find the slope, we'll use the equation m equals the limit as h approach is 0 of f of a plus h minus f of a divided by h.
00:20
So in this case, a is 1.
00:24
So we'll plug in for m the limit as h approaches 0 of f of 1 plus h minus f of 1 divided by h equals the limit as h approaches 0 of 1 plus h minus 1 plus h cubed minus 1 minus 1 cubed.
00:49
All of that divided by h.
00:51
This will cancel out to 0 because it's just 1 minus 1.
00:56
So we'll expand it.
00:59
We will expand the 1 plus h cubed.
01:04
So we'll have the limit as age approach of 0 of 1 plus h minus h cubed plus 3 h squared plus 3h plus 1.
01:16
And all that will be divided by h.
01:19
And to distribute the negative, we will have 1 plus h minus h cubed minus 3h squared minus 3h minus 1.
01:30
And all that's divided by h.
01:32
So we'll combine like terms...