00:01
We want to find this up of the tangent line to the curve.
00:03
Why is he was one of the square root of x at the point x is you go to a then we want to find the equations of the tangent lines at the points 11 and for what? hap.
00:13
And then lastly, we want to graft the curb along with our tangent lines just to make sure they actually line up with each other.
00:22
Now recall to find the soap with sanja line.
00:26
What we're going to do is do the limit as x approaches a oh f of x minus f a all over x minus a.
00:40
Now let's plug everything in.
00:42
What? we have the limit as x approaches a of one over the square root of x minus one over the square root of a all over x minus a.
00:56
Now we can go ahead and combined.
00:59
Our numerator is there or the fractions in the numerator and me to give us square root of a minus root ex all over that was going to be root ex times route a times x minus a.
01:25
Now, if we were to plug in a directly.
01:29
That should be a not infinity right there.
01:32
Now, if we were to plug a and directly, we get 0/0 so we can plug it in quite yet because i don't know, it's there over zero means, but notice that we can factor x minus a in the following fashion.
01:49
It's supposed to be a minus root ex all over root ex route a and that is going to be rude x minus a route x plus a cause that's really just the difference of squares and notice that and both of those should have for someone.
02:12
So let me go ahead and rewrite that again.
02:16
So should be route x minus root a times rue becks plus route a and now notice that this and this are just off by a negative one so we can cancel those out and then just multiply by negative one.
02:36
And now, moving this up here, that should give us the limit as x approaches a of negative one over root ex route a route x plus route a.
02:56
And if we were to go ahead and plug this in now, we would have no issues, and doing that would give us the following so he plugged in a so negative one over.
03:10
So route eight times were a is just a and then route a plus roue would be to route a and now we can go ahead and simplify that down even more to give us negative 1/2 times a to the three halfs powder.
03:32
So this here would be our slope for any point a.
03:36
That this function is to find her now to find the tangent lines at each...