Page 50 - Math SL HB Sem 1

I,-tJNC.r'tONS, [,QUA r IONS, tNriQtJi\LI'I IIi)S

TYPES OF FI]NC'IIONS

I. (]ON,IPOSITE FI]N(]TION

If/ is a function from set X to set I/ and g is a (unction from set y to set Z , the
S(f G\ is the composite function of I follow by g lrom X to Z and denoted by go/
The domain of go/
lf r, ed rthen dot - d1' r] ) 1.

The domain of /og
If rr ed then d ,,r = dg ( 1(\) )ti
,

The condition for the existence of composite functions
For fog to be defined, r* cd,
For g</to be defined, r, cd*

Kamnle I
Given that f(x)-Jx-t and g(x) ln;r. Does fog exist.lf so, dcfine lully thc lunction
=
fog. Ifnot find a suitable restriction on the domain ofg so that/og exists.

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