0:00
Hello.
00:01
So, part a, our original statement is, every isosceles triangle is equilateral.
00:10
Okay.
00:11
Well, for that statement, the negation would be, well, there exists some isosceles triangle that is not equilateral.
00:20
So the negation here would be, there exists.
00:23
I'm trying to take this backwards e.
00:25
This means there exists.
00:26
If you had never seen it before, this is a symbol.
00:28
It means there exists.
00:28
So if there exists an isosceles triangle, an isosceles triangle that is not equilateral.
00:40
That is not equilateral.
00:53
Okay.
00:56
And we recall here that an isosceles triangle is just a triangle with two equal sides.
01:01
An equilateral triangle is a triangle with three equal sides.
01:05
So we know that all equal lateral triangles are also isosceles, but not all isoce triangles are equilateral.
01:12
So therefore, the original statement is certainly false, but the negation of the original statement is true.
01:22
Then for part b, our second statement here is, there is a real number that is not an integer...