HKDSE Mathematics Question Review (2021-01-08)
07/01/21 20:31
Given x+y=6
Find max(xy).
07/01/21 20:33
Answer,
x=y is the optimal.
So we have 2x=6
max(xy) = x^2 = 9
07/01/21 22:14
Sketch the graph for the following equation: xy-2x-2y-2=0
07/01/21 22:16
Sketch the graph for the following equation: xy-2x-2y-2=0
Answer:
It is simply factorization stuff:
(x-2)(y-2) =6
It is an rectangular hyperbola,
with translation of the origin to (2,2).