prep 数学2题求解！

jomisgg

7143-!-item-!-187;#058&005466
59.    7143-!-item-!-187;#058&005466

In the figure above, points P and Q lie on the circle with center O.  What is the value of s ?

(A)  1/2
(B) 1
(C)  √2
(D)  √3
(E)  √2/2
答案：B


18407-!-item-!-187;#058&011575

176.    18407-!-item-!-187;#058&011575

If the operation ? is defined for all integers a and b by a?b = a + b - ab which of the following statements must be true for all integers a, b, and c ?



(A) I only
(B) II only
(C) I and II only
(D) I and III only
(E) I, II, and III

E

sss1119

看不见图啊，亲