Here are some regular expression patterns: \\w one alphanumeric (alphabet or number) character such as w or 2 \\w? optional alphanumeric character The regular expression pattern to match one alphanumeric character is ^\\w$ Write the regular expression pattern to match one alphanumeric character. Examples: a 5 Write the regular expression pattern to match two alphanumeric characters Examples: 16 it A1 Write the regular expression pattern to match three alphanumeric characters Examples: 911 cat ABS Write the regular expression pattern for one optional alphanumeric character followed by one alphanumeric character Examples: 65 it 7 r Write the regular expression pattern for one optional alphanumeric character followed by one optional alphanumeric character followed by one alphanumeric character Examples: 100 cat 65 it 7 r Write the regular expression pattern for two alphanumeric characters followed by an optional alphanumeric character followed by an optional alphanumeric character Examples: 20 it 911 cat 2020 five Write the regular expression pattern for an optional alphanumeric character followed by an optional alphanumeric character followed by two alphanumeric characters Examples: 20 it 911 cat 2020 five