1.
Prompt x
Disp "f(x)="
Disp y1(x)

2.
As x approaches 0, f(x) approaches 1.

3.
Prompt A
Prompt H
(y1(A+H)-y1(A)) / H --> M
Disp M

4.
Prompt A
For (K, 1, 5)
    10^(-K) --> H
    (y1(A+H)-y1(A)) / H --> M
    Disp M
End

5.
Actual slope is 1.