00:03
Number 91.
00:05
In this problem, we explain how a system of three equations with three unknowns could have a unique solution, no solution, or infinitely many solutions if we're thinking of each equation as a plane.
00:18
So i think it would help to visualize something we're familiar with.
00:22
So for a unique solution, imagine that one plane is a wall, and then another plane is an adjacent wall, and then a third plane is a little.
00:35
Floor.
00:37
So we have a wall, a wall, and a floor.
00:43
All three of those intersect in this corner down here.
00:47
So that's an example of a unique solution.
00:51
Moving on to part b, suppose we're looking for a way to explain how there could be no solution.
00:57
Well, you could imagine the ceiling is a plane, and then the floor is a plane, and they're parallel to one another so they don't intersect.
01:08
And then you could imagine something in between like a tabletop is also a plane...