00:01
We'll ask to plot x times the fifth root of x minus 1.
00:05
So x times x minus 1 to the 1 fifth power.
00:12
Obviously when x is 0, our function is 0, so we have 0.
00:20
Now as x gets very, as x gets to be a very negative number, this is going to be negative, and then this is going to be negative.
00:30
So we're going to go off to positive infinity there.
00:33
When x gets very large, this is positive.
00:37
This is positive, so we're going to go off to positive infinity on the right side, as x gets very, is x goes to infinity.
00:46
Now, we can take some derivatives here, and so the first derivative, we get 6x minus 5 all over 5 times x -1 to the 4th, 5th power.
00:58
So again, just using the product rule here, and then some simplifications, we get this.
01:04
And so what do we see here? well, when x is equal to 5 sixth, that we have a vertical horizontal tangent, so that's this point here.
01:15
So 56 is 0 .825.
01:20
So we get this.
01:22
Plugging that back into here, that's minus 0 .58.
01:28
So that point right there is our, we have a horizontal tangent.
01:33
Now clearly we have a vertical tangent and x equals 1.
01:37
So when x equals 1, this thing is 0 again.
01:43
So 1 -0, and we know we have a horizontal tangent there, or a vertical tangent and a horizontal tangent here.
01:50
Now, take another derivative when we get 2 times 3x minus 5 all over 25 x minus 1 to 9 5th.
01:59
Again, after some simplification, you know, using the quotient rule, and then a bunch of simplification, we get this.
02:08
And so that's 0 when x equals 5 thirds, or 1 and 2 thirds, but 1 .67, plug that into here, and we get 1 .5 .4.
02:18
So that's another point.
02:19
That's an inflection point where the curvature is zero.
02:24
And again, we can see that the curvature is infinite at x equals 1...