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A hint to get started

Use partial fractions before sketching an absolute reciprocal

Curve C is f(x)=(x−9)2/[(x−3)(x+3)]f(x)=(x-9)^2/[(x-3)(x+3)].

(i) Express it as P+Q/(x−3)+R/(x+3)P+Q/(x-3)+R/(x+3).

(ii) State all asymptotes and axial intercepts.

(iii) Sketch separately (a) y=f(x)y=f(x) and (b) y=∣1/f(x)∣y=|1/f(x)|, making the main features clear.

[2007/CJC/I/12]

CJC · Discussion · Question 7

Read the absolute-value bars in the printed final ask; the signed reciprocal is only an intermediate sketch.

Read the worked solution