Respuesta :
Answer:
The probability that the device fails during its first hour of operation is 0.625.
Step-by-step explanation:
The joint density function of the lifetimes of the two components, both measured in hours, is:
[tex]f(x,y)=\frac{x+y}{8};\ 0<x<2,\ 0<y<2[/tex]
Compute the probability that the device fails during its first hour of operation as follows:
[tex]P[(X<1)\cup (Y<1)]=1-\int\limits^{2}_{1} {\int\limits^{2}_{1} {\frac{x+y}{8}} \, dx } \, dy[/tex]
[tex]=1-\int\limits^{2}_{1} {\frac{x^{2}+2xy}{16}}|^{2}_{1} \, dy\\\\=1- \int\limits^{2}_{1}[{\frac{4+4y}{16}-\frac{1+2y}{16}}] \, dy\\\\=1-\int\limits^{2}_{1}{\frac{3+2y}{16}}\, dy\\\\=1-[\frac{3y+y^{2}}{16}]^{2}_{1}\\\\=1-0.375\\\\=0.625[/tex]
Thus, the probability that the device fails during its first hour of operation is 0.625.
