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Given A = {1, 2, 3, 4, 5}, S = {(x, y) : x ∈ A, y ∈ A}. Find the ordered pairs which satisfy the conditions given below:(i) x + y = 5(ii) x + y < 5(iii) x + y > 8 |
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Answer» According to the question, A = {1, 2, 3, 4, 5}, S = {(x, y) : x ∈A, y ∈A} (i) x + y = 5 So, we find the ordered pair such that x + y = 5, where x and y belongs to set A = {1, 2, 3, 4, 5}, 1 + 1 = 2≠5 1 + 2 = 3≠5 1 + 3 = 4≠5 1 + 4 = 5⇒ the ordered pair is (1, 4) 1 + 5 = 6≠5 2 + 1 = 3≠5 2 + 2 = 4≠5 2 + 3 = 5⇒ the ordered pair is (2, 3) 2 + 4 = 6≠5 2 + 5 = 7≠5 3 + 1 = 4≠5 3 + 2 = 5⇒ the ordered pair is (3, 2) 3 + 3 = 6≠5 3 + 4 = 7≠5 3 + 5 = 8≠5 4 + 1 = 5⇒ the ordered pair is (4, 1) 4 + 2 = 6≠5 4 + 3 = 7≠5 4 + 4 = 8≠5 4 + 5 = 9≠5 5 + 1 = 6≠5 5 + 2 = 7≠5 5 + 3 = 8≠5 5 + 4 = 9≠5 5 + 5 = 10≠5 Therefore, the set of ordered pairs satisfying x + y = 5 = {(1,4), (2,3), (3,2), (4,1)}. (ii) x + y < 5 So, we find the ordered pair such that x + y<5, where x and y belongs to set A = {1, 2, 3, 4, 5} 1 + 1 = 2<5 ⇒ the ordered pairs is (1, 1) 1 + 2 = 3<5 ⇒ the ordered pairs is (1, 2) 1 + 3 = 4<5 ⇒ the ordered pairs is (1, 3) 1 + 4 = 5 1 + 5 = 6>5 2 + 1 = 3<5 ⇒ the ordered pairs is (2, 1) 2 + 2 = 4<5 ⇒ the ordered pairs is (2, 2) 2 + 3 = 5 2 + 4 = 6>5 2 + 5 = 7>5 3 + 1 = 4<5 ⇒ the ordered pairs is (3, 1) 3 + 2 = 5 3 + 3 = 6>5 3 + 4 = 7>5 3 + 5 = 8>5 4 + 1 = 5 4 + 2 = 6>5 4 + 3 = 7>5 4 + 4 = 8>5 4 + 5 = 9>5 5 + 1 = 6>5 5 + 2 = 7>5 5 + 3 = 8>5 5 + 4 = 9>5 5 + 5 = 10>5 Therefore, the set of ordered pairs satisfying x + y< 5 = {(1,1), (1,2), (1,3), (2, 1), (2,2), (3,1)}. (iii) x + y > 8 So, we find the ordered pair such that x + y>8, where x and y belongs to set A = {1, 2, 3, 4, 5} 1 + 1 = 2<8 1 + 2 = 3<8 1 + 3 = 4<8 1 + 4 = 5<8 1 + 5 = 6<8 2 + 1 = 3<8 2 + 2 = 4<8 2 + 3 = 5<8 2 + 4 = 6<8 2 + 5 = 7<8 3 + 1 = 4<8 3 + 2 = 5<8 3 + 3 = 6<8 3 + 4 = 7<8 3 + 5 = 8 4 + 1 = <8 4 + 2 = 6<8 4 + 3 = 7<8 4 + 4 = 8 4 + 5 = 9>8, so one of the ordered pairs is (4, 5) 5 + 1 = 6<8 5 + 2 = 7<8 5 + 3 = 8 5 + 4 = 9>8, so one of the ordered pairs is (5, 4) 5 + 5 = 10>8, so one of the ordered pairs is (5, 5) Therefore, the set of ordered pairs satisfying x + y > 8 = {(4, 5), (5, 4), (5,5)}. |
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