CUSTOMER_CODE SMUDE DIVISION_CODE SMUDE EVENT_CODE SMUAPR15 ASSESSMENT_CODE MCA1030_SMUAPR15 QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 10111 QUESTION_TEXT Explain the 2 methods of representing a set SCHEME OF EVALUATION There are two methods of representing a set: i.Roster or tabular form ii.Set builder form i.In roster form, all the elements of a set are listed, the elements being separated by commas and are enclosed within braces { }. For example, the set of all even positive integers less than 7 is described in roster form as {2, 4, 6}. It may be noted that while writing the set in roster form an element is not generally repeated, i.e all the elements are taken as distinct. ii.In set builder form, all the elements of a set possess a single common property which is not possessed by any element outside the set. For example, in the set “{a, e, i, o, u}” all the elements possess a common property, each of them is a vowel in the English alphabet and no other letter possesses this property. Denoting this set by V, we write V= {x: x is a vowel in the English alphabet} QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 10114 QUESTION_TEXT Define the following with an example: Empty set, finite and infinite set, equal sets, subsets, powerset SCHEME OF EVALUATION Solution: Empty set: A set which does not contain any element is called an empty set or null set Ex: P={x:1<x<2, x is a natural number} Finite and infinite set: A set which is empty or consists of a definite number of elements is called finite. Otherwise the set is called infinite. Ex: A={1, 2, 3, ….}infinite B={1, 2, 3}finite Equal sets: 2 sets A and B are said to be equal if they have exactly the same elements and we write A=B Ex: Let A ={1, 2, 3, 4}, B={3, 4, 1, 2} Then A=B Subsets: If every element of a set A is also an element of a set b, then A is called a subset of B denoted by A C B Ex: A={1, 2, 3, 4}, B={0, 1, 2, 3, 4, 5} Then A C B Power set: The collection of all subsets of a set A is called the power set of A, denoted by P(A) Ex: A={1, 2} Then P(A)= {∅, {1}, {2}, {1, 2}} QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 74003 QUESTION_TEXT Let p: The south-west monsoon is very good this year. q: Rivers are rising Give the verbal translation of i. ~ [(~p) v (~q)] ii. p q iii. (p v q) v (~p) iv. ~ (p ^ q) v. (~p) ^ (~q) SCHEME OF EVALUATION i. The south-west monsoon is very good this year and rivers are rising. ii. If the south-west monsoon is very good this year then the rivers are rising. iii. The south-west monsoon is very good this year or the rivers are rising or the south-west monsoon is not very good this year. iv. The south-west monsoon is not very good this year or the rivers are not rising. v. The south west monsoon is not very good and the rivers are not rising. (2 5 = 10 marks) QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 74004 Explain the cartesian product of Sets. QUESTION_TEXT SCHEME OF EVALUATION Solution: Let A, B be two sets. If a is in A, b is in B, then (a, b) denotes an ordered pair whose first component is a and the second component is b. Two ordered pairs (a, b) and (c, d) are said to be equal if and only if a = c and b = d. (2 marks) In the ordered pair (a, b), the order in which the elements a and b appears in the bracket is important. Thus (a, b) and (b, a) are two distinct ordered pairs if a not equal to b. Also, an ordered pair (a, b) is not the same as the set {a, b}. (2 marks) Definition: The set of all ordered pairs (a, b) of elements a is in A, b is in B is called the Cartesian Product of sets A and B and is denoted by A x B. Thus A x B={(a, b): a is in A, b is in B}. Let A={a1, a2}, B={b1, b2, b3. To write the elements of A x B, take a1 is in A and write all elements of B with a1, i.e., (a1, b1), (a1, b2), (a1, b3). Now take a2 belongs to A and write all the elements of B with a2, i.e., (a2, b1), (a2, b2), (a2, b3). Therefore, A x B will have six elements, namely (a1, b1), (a1, b2), (a1, b3), (a2, b1), (a2, b2), (a2, b3) (6 marks) QUESTION_TYP DESCRIPTIVE_QUESTION E QUESTION_ID 124969 Let A={1, 2, 3}, B={3, 4} and C={4, 5, 6}. Then find i. A×(B∩C) QUESTION_TEX ii. (A×B)∩(A×C) T iii. A×(B∪C) iv. (A×B)∪(A×C) SCHEME OF EVALUATION i. We have ii. We note that and . Therefore, Therefore iii. Clearly iv. In view of (ii), we see that . Thus QUESTION_TYPE DESCRIPTIVE_QUESTION QUESTION_ID 124975 QUESTION_TEXT Explain the concept of complex numbers. Briefly explain two properties of complex numbers for addition and multiplication. Let C denote the set of all ordered pairs of real numbers. SCHEME OF EVALUATION i.e., C = {(x, y) : x, y R} on this Set C define addition ‘+’ and multiplication ‘.’ by (x1, y1) + (x2, y2) = (x1 + x2 , y1 + y2) → (1) (x1, y1) . (x2, y2) = (x1 x2 – y1y2, x1y2 + x2y1) → (2) Then the elements of C which satisfy the above rules of addition and multiplication are called complex numbers. (2 marks) Properties of addition1. Closure law : If z1 = (x1,y1), z2 (x2, y2) Then from Equation (1) z1+ z2 = (x1,y1) + (x2, y2) = (x1 + x2, y1+y2) Which is also ordered pair of real numbers. Hence z1+z2 C, therefore for every z1, z2 C, z1+z2 C (2 marks) 2. Associate law : z1+(z2 + z3) = (z1+ z2) + z3 for every z1, z2, z3C (2 marks) Similarly other any 3 properties can be explained. Properties of multiplication1. Closure law : If z1 = (x1, y1), z2 = (x2, y2)C then from (2) (2 marks) z1, z2 = (x1, y1) (x2, y2) = (x1x2 – y1y2, x1y2 + x2y1) Which is also an ordered pair of real number. Hence z1, z2 is also a complex number. Thus for every z1, z2C, z1z2C 2. Existence of identity element : There exists (1, 0) C such that (x, y)(1, 0) = (x.1 –y.0, x.0 + 1.y) = (x, y) for every (x, y) C. Here (1, 0) is called the multiplicative identity element. (2 marks) Similarly other any three properties can be explained.