5. In a box there are R red balls and B black balls. In an experiment, we randomly pick a ball from the box, record its color and then throw the ball back to the box. We then repeat the random picking N times. Let X be the total number of red balls picked. We assume R, B and N are all positive integers.
(2) We now change the experiment setup. When a ball is picked, it is removed from the box for the rest of the experiment. Let N be no greater than R+B. What is the mean value of X now?
(1) What is the mean value of X?
(2) A Boolean variable can have either the value "T" which stands for true or "F" which stands for false. List all values of the Boolean variables X, Y and Z so that (X + Y + not(Z)) = X dot Y dot Z
25. 若f(x)=x4+5x3+x-1,g(x)=x2-2 且 f (x) 除以 g(x) 的餘式為ax+b ( a , b為常數),則2a-3b 為何? (A) -27 (B) -7 (C) 5 (D) 13
23. 已知點 P(a-b,ab) 在坐標平面的第四象限,則下列敘述何者正確? (A) A(a,-b ) 在第一象限 (B) 在第二象限 (C)
在第三象限 (D)
在第四象限
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