(i) A truth table shows how the truth or falsity of a compound statement depends on the truth or falsity of the simple statements from which it's constructed.

Since A ∧ B (the symbol ∧ means A and B) is true only when both A and B are true, its negation A NAND B is true as long as one of A or B is false.

Since A ∨ B (the symbol ∨ means A or B) is true when one of A or B is true, its negation A NOR B is only true when both A and B are false.

Below are the truth tables for NAND and NOR connectives.

(ii) To show that (A NAND B)∨(A NOR B) is equivalent to (A NAND B) we build the truth table.

Since the last column (A NAND B)∨(A NOR B) is equal to (A NAND B) it follows that the statements are equivalent.

(iii) To show that (A NAND B)∧(A NOR B) is equivalent to (A NOR B) we build the truth table.

Since the last column (A NAND B)∧(A NOR B) is equal to (A NOR B) it follows that the statements are equivalent.

6 0

3 years ago

As of April 2006, roughly 50 million web domain names were registered (e.g., ). How many domain names consisting of just two let

Furkat [3]

Answer:

a) 676, 1296

b) 17576, 46656

c) 456976, 1679616

Step-by-step explanation:

firstly we know that there are 26 letters in the alphabet.

there are 26 ways of choosing the first character and 26 ways choosing the second character,

Therefore, the possible number of domains with two leeter is;

n = 26²

= 26 × 26

= 676

now when the digits are allowed, there are 26 + 10 = 36 characters to be used in total

therefore the possible number of domains with two characters is;

n = 36²

= 36 × 36

= 1296

there are 26 ways of choosing each character

therefore, the possible number of domains with three letters is

n = 26³

= 26 × 26 × 26

= 17576

when the digits are allowed, there are 26 + 10 = 36 characters to be used in total

therefore , the possible number of domains with three characters is;

n = 36³

= 36 × 36 × 36

= 46656

there are 26 ways of choosing each character, therefore the possible number of domains with four letters is;

n = 26⁴

n = 26 × 26 × 26 × 26

n = 456976

when the digits are allowed, there are 26 + 10 = 36 characters to be used in total

therefore, the possible number of domains with four characters is;

n = 36⁴

n = 36 × 36 × 36 × 36

= 1679616

7 0

3 years ago