Here it is. Two easy questions I think but it could make my worksheet easier!
K := x - x y + y = 27
2 x - y
afg1 := -------
x - 2 y
When is the tangent horizontal or vertical?
[[x = y/2, y = y]]
[[x = 2 y, y = y]]
Which points are these?.
---- = 27
Now is my question if there is an easier way to substitute this points. I have calculated the
2 values for y but could not substitute them in K because I had already substituded x = y/2
in it. It would result in an error. Is there an easy way to reset K or do I have to restart
all over? A second questions is if I could put the 2 solve commando's from the first
deriviative in one command. Something like solve(afg1=0 and 1/afg1=0,[x,y]). Thank you :)