00:03
The first problem we want to prove the absolute value function is continuous everywhere.
00:11
So first, so this is the absur's function.
00:15
And to say we want to prove f of x is continuous at 1 point, say x equal to a.
00:22
Then we can see the difference of the function.
00:26
So this, if you write, it is actually equal to absolute value of x minus absolute value.
00:34
Value of a.
00:36
And if you use a triangle inequality, you can prove this is smaller than absolute value of x minus a.
00:45
So when x tend to a, you'll see x minus a is 10 to 0.
00:54
So this means you can say this function is the upper bounds we sometimes goes to 0 than f of x minus f a.
01:03
So this one also.
01:05
Tends to 0.
01:08
So that means the function f is continuous at x equal to a.
01:12
And here a is like arbitrary.
01:16
So f of x is continuous everywhere.
01:21
And for the second problem, so we want to prove that f is continuous.
01:28
Then similarly for absolute value of x...