# Person: Al-Nasawi

Al-Nasawi was an Islamic mathematician who wrote summaries of some of Euclid's Elements.

### Mathematical Profile (Excerpt):

• Al-Nasawi had prepared an original version of it in Persian for the library of the Iranian prince Majd al-Dawlah, of the Buyid dynasty.
• Before the work was completed, however, Majd al-Dawlah was deposed as ruler so, on completion of the work, al-Nasawi presented it to Sharaf al-Muluk who was the vizier of Jalal ad-Dawlah (Jalal ad-Dawlah was the ruler of Baghdad from 1025 to 1044).
• Sharaf al-Muluk ordered al-Nasawi to rewrite the work in Arabic, and this he did.
• From this description, and from the fact that al-Nasawi dedicated another work to a Shi'ite leader in Baghdad, we at least can deduce that al-Nasawi worked for part of his life in Baghdad.
• A paragraph about al-Nasawi's life has been found in a manuscript and it tells us that he spent time in Rayy, and was visited by ibn Sina.
• Tract 26 is a summary of Euclid's Elements by al-Nasawi.
• The reasons which al-Nasawi gives for writing this summary are two-fold.
• All al-Nasawi appears to have done is to omit some constructions and change a few of the proofs.
• The arithmetic book by al-Nasawi is of this third "Indian numeral" type.
• In each of the four cases al-Nasawi explains the four elementary arithmetical operations.
• Each method for each of the four types is illustrated with worked examples and a checking procedure is explained which usually involves usually casting out nines The method al-Nasawi gives for taking cube roots is the same as the method described in the Chinese Mathematics in Nine Books, but quite how he learnt of this method is unknown.
• Al-Nasawi is critical of works on arithmetic written by earlier authors.
• In fact, in some respects, al-Nasawi does not rate too highly as a mathematician.
• There seems nothing original in any of his works and, more significantly, there are several places where al-Nasawi presents pieces of mathematics which he fails to properly understand.
• Two other works by al-Nasawi have survived.

View full biography at MacTutor

Ancient Arab, Origin Iran

Thank you to the contributors under CC BY-SA 4.0!

Github:

non-Github:
@J-J-O'Connor
@E-F-Robertson

### References

#### Adapted from other CC BY-SA 4.0 Sources:

1. O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive