Applications of the Focus Point.
1. Two pairs of data, $(1,2)$ and $(2,0)$determine
a linear function, $f$.
Solution: Draw the arrows on the Mapping
Diagram and extend them if needed to meet at the Focus Point.
To find $f(0)$ on the MD, draw the line from the
focus point through $0$ on the Domain Axis . Where the line meets
the Target Axis is $f(0)$.
2. Using the same function as in the
previous problem find $a$ where $f(a)= 1$.
Solution: Draw the line from the focus point of $f$ to $1$
on the Target Axis. Where this line meets the Domain Axis, is the
desired value for $a$.