Porisma

A hint to get started

Invert an exponential and distinguish a composite from a square

(a) The functions ff and gg are defined by

f:x↦e1−x2f:x\mapsto e^{1-x^2}, x>0x>0,

g:x↦1+xxg:x\mapsto\dfrac{1+x}{x}, x>0x>0.

(i) Find, in a similar form, f−1f^{-1} and g2g^2. marks

(ii) Sketch the graph of g2g^2 and write down the range of values of mm such that g2(x)=mx+2g^2(x)=mx+2 has no real roots for x>0x>0. marks

(b) The functions hh and kk, each with domain R\mathbb R, are such that

h:x↦(x−1)2+5h:x\mapsto(x-1)^2+5,

kh:x↦2x2−4x+15kh:x\mapsto2x^2-4x+15.

Find the function kk. marks

[2010/PJC/Promo/4]

CJC · Review Problems · Question 4

For g², substitute g(x) into g; for k, first determine which inputs h can ever supply.

Read the worked solution