Tham KY's answer to trish's Junior College 1 H2 Maths Singapore question.

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Tham KY
Tham Ky's answer
6052 answers (Tutor Details)
trish
Trish
3 years ago
thank you so much! but could you explain how you got f(x)= 1+ a-b/x+b? thank you
trish
Trish
3 years ago
also, if you don’t mind, could you also explain the line “since x=1 is the asymptote, f^-1(x)= (x+a)/b-1 and hence b= -1”? thank you so much
Tham KY
Tham KY
3 years ago
You do long division will get the partial fraction out...
Tham KY
Tham KY
3 years ago
x=1 is the vertical asymptote. If you have learnt Graphing techniques, you will know.
In short, you make the denominator of that fraction equal to zero, you will get the equation of vertical asymptote.
Tham KY
Tham KY
3 years ago
You typed wrongly in your second comment: denominator should be "x-1", not "b-1".
Since the denominator was written as "x+b", equate it to zero gets x+b=0, rearrange gets x=-b, the equation of the vertical asymptote of x=1, hence -b must be equal to 1, therefore b=-1.
trish
Trish
3 years ago
oh ok i get it now, thank you so much for your help!