(2b) Let I = {2,4, 6, 8, 10} and S« = { a | a E I}. Prove or disprove the following statement: "If S = Uaei Sa, then |S| = 10."

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prove in words: If {X, Y, Z} ` A ∧ ¬A, then {Y, Z} ` ¬X ` = derivability

Confused as to where/how you derived  p(A∪B') = P(A) + P(A'∩B'). Am I missing something from a thereom?

Which postulate justifies that ДНАМ-ДСОW? H. а. АА C. ASA b. SSA d. SAS

5) Let U = {0,1,2,3,4,5,6,7,8,9,10}; A = {0,1,2,3,5,8}; B = down the elements in the following sets. (a) AUB (b) BUC (c) BC (d) (A' n C) UB (e) n((A UC) n B) = {0,2,4,6}; C = {1,3,5,7}. Write

prove that (1, 6) 13 an o pen set 13 an open çet.

6. |{Xe 9({0,1,2,3,4,5,6,7,8,9}):|X|=4}|=

Show that (N,|) is a poset.

Let a1, a2, ... , a, E N. Show that if a1 , a2, ... , az are consecutive, then 7| (a, + az + ... + a7) .....