InterviewSolution
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Write down the negation of following compound statements.(i) All rational numbers are real and complex.(ii) All real numbers are rationals or irrationals.(iii) x = 2 and x = 3 are roots of the quadratic equation x2 -5x +6 = 0(iv) A triangle has either 3-sides or 4-sides.(v) 35 is a prime number or a composite number.(vi) All prime integers are either even or odd.(vii) |x| is equal to either x or -x.(viii) 6 is divisible by 2 and 3. |
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Answer» (i) Let p: All rational numbers are real. q: All rational numbers are complex. ~ p: All rational numbers are not real. ~ q ; All rational numbers are not complex. Then, the negation of the given compound statement is: ~ (p ∧ q): All rational numbers are not real or not complex. [~(p ∧ q) = ~p v ~q] (ii) Let p: All real numbers are rationals. q: All real numbers are irrationals. Then, the negation of the given compound statement is: ~ (p v q): All real numbers are not rational and all real numbers are not irrational. [~(p v q) = ~p ∧ ~ q] (iii) Let p ; x = 2 is root of quadratic equation x2 – 5x + 6 = 0. q: x = 3 is root of quadratic equation x2 – 5x + 6 = 0. Then, the negation of the given compound statement is: ~ (p ∧ q) : x = 2 is not a root of quadratic equation x2 – 5x + 6 = 0 or x = 3 is not a root of the quadratic equation x2 – 5x + 6 = 0. (iv) Let p: A triangle has 3-sides. q: A triangle has 4-sides. Then, the negation of the given compound statement is: ~ (p v q): A triangle has neither 3-sides nor 4-sides. (v) Let p: 35 is a prime number. q: 35 is a composite number. Then, the negation of the given compound statement is: ~ (p v q): 35 is not a prime number and it is not a composite number. (vi) Let p: All prime integers are even. q: All prime integers are odd. Then, the negation of the given compound statement is given by ~(p v q): All prime integers are not even and all prime integers are not odd. (vii) Let p:|x| is equal to x. q: |x| is equal to —x. Then, the negation of the given compound statement is: ~ (p v q): |x| is not equal to JC and it is not equal to —x. (viii) Let p: 6 is divisible by 2. q: 6 is divisible by 3. Then, the negation of the given compound statement is: ~ (p∧q): 6 is not divisible by 2 or it is not divisible by 3 |
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