The region R^2 for positive values of x 1 and x 2 is shown as the shaded area in
F igure 5.18. H ence,
y
fY(y)
01
1
2
2
Figure 5. 17 Probability density function, fY (y), in Example 5.11
x 1
x— 2
=y
R^2
x 2
x 1
Figure 5. 18 Region R^2 in Example 5.12
Functions of Random Variables 141
FY
y
Z 1
0
Zx 2 y
0
fX 1 X 2
x 1 ;x 2 dx 1 dx 2 ; fory> 0 ;
0 ; elsewhere: