Q.State whether the following sentence is a statement. Justify your answer. In case it is a statement, state its truth value: Close the door.

A statement in mathematical logic is a declarative (assertive) sentence that has exactly one truth value: it is either true (denoted T) or false (denoted F), never both at once and never undetermined. Statements are named using lowercase letters such as p, q, r for convenience. Sentences that ask a question, give a command or request, express an exclamation, or whose truth genuinely depends on who is speaking, when, or on an unassigned variable (for example 'x + 6 = 9', 'he is tall', or 'it is black in colour') are called open sentences and are NOT statements in logic, because no single fixed truth value can be pinned to them. Recognising whether a sentence is a statement, and if so assigning its correct truth value, is the entry point for every later idea in this chapter — every truth table, every logical law, and every switching circuit ultimately rests on a collection of such T/F-valued statements.