Weird Math question in BB page 329

TomBor
Wed, 04 Nov 2009 10:53:47 +0000

In page 329, q15.
I’m really confused by their explanation.

I understand that the slope of RS is 1.
But could T be right angle, with RT a slope of 0 and… Well, TS will be undefined. Is this why that is a problem? Because the slope of TS is undefined?

If the slope can’t be undefined, that would make much more sense.
I mean, how do you add an undefined value?..