Matematicamente.it

Mi sono iscritto all'università online inglese OpenUniversity. Nel testo del primo corso di matematica trovo questa definizione
"An expression such as 1−2√5 is called a surd."

Non conoscevo il termine Surd, che scrivono derivare dal latino Surdus, come Absurd ... in italiano si usa?

I don't know
Anyway, can you write in English here? Please
Have you got any troubles in attending an online University?

it means "irrazionale".

I have just enroled OpenUniversity. In the book of the first math course I find this definition
"An expression such as 1−2√5 is called a surd."

I am 50 years old. I studied at "Liceo Scientifico" ... never heard this word, "A SURD" ... how is in Italian?

I cannot really answer your question because the course start on 7 October, anyway I suppose the continuous assessment system is a good thing. I hope it can help me to Graduate! I chose BSc (Honours) Computing & IT and Mathematics: 12 course in total and just 7 with a Final Examination. First course will have an open book examination, I don't know the other.
The first Tutor marked assertament is about unit 1 and 2 ... one question is a problem: you know the diameter of a circonference and the perimeter of a square and you have to "criticize" a very synthetic solution and to write down a complete solution: "Which field has the largest area?". I suppose that my son in 3rd Secondary school, as soon as he will learn circonference, will be able to give a complete and exhaustive solution!

Anyway this is just first course and first TMA so I have time to have problem!

In the future I will give more information about studying Maths and Computer Science at Open University.

cooper ha scritto:it means "irrazionale".

irrazionale in Italian is an adjective, "A surd" is noun!

that's because I was inaccurate. it can be thought both as a noun and an adjective. when it is thought like a noun it stands for "numero irrazionale".

cooper ha scritto:that's because I was inaccurate. it can be thought both as a noun and an adjective. when it is thought like a noun it stands for "numero irrazionale".

An other quote from the same book:
"Note that in some texts, the word ‘surd’ means ‘irrational root’ rather
than ‘numerical expression containing one or more irrational roots’."

It seems that the word "Surd" is not a generic "Irrational number" but a specifical number linked with "irrational root"!
"e", "π" or other Irrational Number are not "surd" according to that book.

uhm I don't know. I always (big word actually ) used in the sense: "not expressilbe as the ratio of two whole number" and I used it for $pi$ as well. maybe your book has a different definition but I can't get it, thogh.

As far as I know, though "surd" is said to derive from the Latin word "surdus", there is a little problem concernig its use in Mathematics. "Surdus" is a medioeval Latin word, it does not come from the classical or ancient Latin, while absurd exists since Romans. Why some numbers are called "blind" or "deaf"(the meanings of "surdus")? There was an error of translation from arabic: when European mathematicians face their Arab colleagues using the term jadr, they traduced it as "deaf" or "blind", because in Arabic that word is used for both those handicaps, and in Latin the equivalent was "surdus". But they forgot - or did not know - that Arabic word has also another meaning: "bizarre", "strange", "uncommon"¹, while in Latin those further meanings are not of "surdus". The time passed and the term survived.

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