Given functions f:{ 1,3,4 }→{ 1,2,5 } and g:{ 1,2,5 }→{ 1,3 } are defined by f={ ( 1,2 ),( 3,5 ),( 4,1 ) } and g={ ( 1,3 ),( 2,3 ),( 5,1 ) } respectively.
We know that,
gof( 1 )=g( f( 1 ) ) =g( 2 ) =3
gof( 3 )=g( f( 3 ) ) =g( 5 ) =1
gof( 4 )=g( f( 4 ) ) =g( 1 ) =3
Therefore, gof={ ( 1,3 ),( 3,1 ),( 4,3 ) }.