Final answer:
The symbolic form of the compound statement 'The Earth is round and it is not flat', using the letters 'w' for 'The Earth is round' and 'z' for 'The Earth is flat', is expressed as 'w ∧ ¬z'.
Step-by-step explanation:
To express the compound statement 'The Earth is round and it is not flat' in symbolic form using the given letters, we can translate this into symbolic logic. The letter 'w' symbolizes the statement 'The Earth is round', and the letter 'z' symbolizes the statement 'The Earth is flat'. The logical connector 'and' corresponds to the logical conjunction symbol '∧', and 'not' corresponds to the logical negation symbol '¬'. Therefore, the compound statement can be expressed symbolically as:
w ∧ ¬z.