Back to 11.3 Problems on Mathematical Expectation

11.3 Exercise 30

Avg difficulty 2.5

(See Exercise 20 from "Problems On Random Vectors and Joint Distributions"). fXY(t,u)=12227(3t+2tu)f_{X Y} \left(t , u\right) = \frac{12}{227} \left(3 t + 2 t u\right), for 0≤t≤20 \leq t \leq 2, 0≤u≤min{1+t,2}0 \leq u \leq \min \left\{1 + t , 2\right\}.

f X ( t ) = I [ 0 , 1 ] ( t ) 12 227 ( t 3 + 5 t 2 + 4 t ) + I ( 1 , 2 ] ( t ) 120 227 t f_{X} \left(t\right) = I_{\left[0 , 1\right]} \left(t\right) \frac{12}{227} \left(t^{3} + 5 t^{2} + 4 t\right) + I_{\left(1 , 2\right]} \left(t\right) \frac{120}{227} t
f Y ( u ) = I [ 0 , 1 ] ( u ) 24 227 ( 2 u + 3 ) + I ( 1 , 2 ] ( u ) 6 227 ( 2 u + 3 ) ( 3 + 2 u - u 2 ) f_{Y} \left(u\right) = I_{\left[0 , 1\right]} \left(u\right) \frac{24}{227} \left(2 u + 3\right) + I_{\left(1 , 2\right]} \left(u\right) \frac{6}{227} \left(2 u + 3\right) \left(3 + 2 u - u^{2}\right)
= I [ 0 , 1 ] ( u ) 24 227 ( 2 u + 3 ) + I ( 1 , 2 ] ( u ) 6 227 ( 9 + 12 u + u 2 - 2 u 3 ) = I_{\left[0 , 1\right]} \left(u\right) \frac{24}{227} \left(2 u + 3\right) + I_{\left(1 , 2\right]} \left(u\right) \frac{6}{227} \left(9 + 12 u + u^{2} - 2 u^{3}\right)

Pfeiffer, Applied Probability, 11.3 Problems on Mathematical Expectation, exercise 30

AI Tutor

Adapted from Applied Probability © 2009 Paul E. Pfeiffer. Licensed under CC BY 3.0. Source: Applied Probability. Imported at revision d7a0420.