A logarithmic involution
(a) The curve has horizontal asymptote and cuts the axes at and , where are non-zero constants. Given that exists, state if possible the coordinates where the following curves cut the axes and their asymptotes: (i) , (ii) . marks
(b) for , .
(i) Find and state its domain. marks
The function for , .
(ii) Find the exact solutions of in simplest form. marks
[2021/NYJC/Prelim/I/5]
Solution
If this part uses an earlier result, revisit (a)i Transformations of intercepts or open all working together.
Inverse functions
State, if possible, where cuts the axes and its asymptote.
Hint
Reflecting in swaps the coordinates of every point.
A reflection in turns horizontal lines into vertical lines.
Answer · (a)ii
Intercepts ; asymptote .
Swap coordinates
If then .
Swap the asymptote
A horizontal asymptote becomes a vertical one.