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(first) in this problem i want to know why integral range defined like that (0 t

ID: 3340165 • Letter: #

Question

(first)

in this problem

i want to know why integral range defined like that (0 to y)

why define zero to y not zero to 1

(second)

why dy's integral range defined x to 1?

is it possible 1 to y?

(third)

why dx's integral range defined y to 0?

is it possible y to 1/2?

i want to understand why range definded like that

0, otherwise. Example 5.7-1 Suppose that the joint PDF for random variables X and Y is given by xy(x,y)"(0, otherwise. 2y Determine(c) (n(x) and f,(y,and the probability that Solution: We first determine the value of constant c //fry(x,y)drdy. = 1 j[Icdr|dy=1. cy 0

Explanation / Answer

1. The range of X and Y are dependent on each other. So,

while determining the value of c, we have to integrate over

the ranges of X and Y. We should have one dependent and

other one as independent range. So we can keep the range of

Y as independent i.e. 0 to 1 and range of X as dependent i.e.

0 to Y. Also, we can keep range of X as independent i.e. 0 to 1

and range of Y as dependent i.e. X to 1.

2. While computing the marginal density of X and as the range

of Y is dependent on X, we should have the integral of Y as

X to 1. It can't be 1 to y, as we are integrating over Y.

3. While computing marginal density of Y, we have to integrate

over X and the range of X, being dependent on Y, we should

have the integral from 0 to Y. It can't be from y to 1/2, as for

x > 1/2, the integral value will not be there.