Question from Book:
What symmetry property does the word “zoonosis” have when written in uppercase letters?
Answer from Book: It is symmetric under a horizontal reflection.
This seems wrong. If we reflect ZOONOSIS horizontally we don't get back ZOONOSIS, the Z, N, and S are facing the wrong way.
Name of book is Contemporary Algebra by Joseph. A Gallian, Eighth edition.
On Symmetries... I have a doubt about the book's answer.?
2020-12-30 7:23 pm
回答 (2)
2020-12-30 8:04 pm
You are correct. The official answer is wrong.
However, each letter of ZOONOSIS has 180º rotational symmetry and this makes ZOONOSIS the longest word in the English language composed entirely of letters having this symmetry.
However, each letter of ZOONOSIS has 180º rotational symmetry and this makes ZOONOSIS the longest word in the English language composed entirely of letters having this symmetry.
2020-12-30 8:46 pm
Anonymous has the right answer here. The symmetries of the letters do give you a symmetry for the whole word, but it's not one of the standard ones. (Remember that a symmetry is simply something you can do to an object that leaves it unchanged.)
If you rotate ZOONOSIS 180 degrees about its center, you get SISONOOZ. Reverse the order of the letters and you're back to ZOONOSIS again. So the compound operation of (rotate by 180, then reverse the letters) is a symmetry of this word.
If you rotate ZOONOSIS 180 degrees about its center, you get SISONOOZ. Reverse the order of the letters and you're back to ZOONOSIS again. So the compound operation of (rotate by 180, then reverse the letters) is a symmetry of this word.
收錄日期: 2021-04-24 08:07:40
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