A = ( k − 2 1 − k k ) , where k is...
Answer & Explanation
The line is mapped to itself if we have that for each point on the line also lies on the line. We needn't have for all , it suffices to have for all and some function .
Having this in mind, we look at . We must have for to lie on our line. This gives
On the same line (!) of thought: the line is the same as the vector space , or if you prefer: , and then what we really want to happen is
so and thus