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Answer: PQ=5, QR=radical 61= 7.81, angle: 50degrees,</span>Why:PQ=|-3|+2=5PR=6<span>angle Alfa, so there is right angle triangle PQR so I can use following formula:</span>PQ^2 + RP^2=QR^2;25 + 36=QR^2;QR=radical 61<span>also I can use: sinus (angle)=PR/QR;</span><span>sin(angle)=6/radical61=0.76822 which gives angle to be little bit more than 50 degrees{sinus 50 degrees=<span>0,7660</span>}. </span>
The answer here is the answer (a). This is because it only makes sense to just read the problem and see that the water stands in race A are closer together.
Use the definitions of expectation and variance.
Integrate by parts,
with
Then
(since the integral of the PDF is 1, and this integral is 4 times that)
Compute the so-called second moment.
Integrate by parts, with
Then
and the variance is