Persia · c. 1135-c. 1213
Sharaf al-Din al-Tusi
Sharaf al-Din al-Tusi was mathematician and astronomer. He analyzed cubic equations and studied conditions under which they have positive roots.
Biographical and historical reference works document Sharaf al-Din al-Tusi’s role and the mathematical work summarized on this page.
6-8, 9-12, College
The person and the work
Biography
Sharaf al-Din al-Tusi was mathematician and astronomer associated with Persia. He analyzed cubic equations and studied conditions under which they have positive roots.
His treatment connected the maximum value of an expression with the number of possible roots. Together, these contributions connect algebra and functions and calculus and change to the working problems, tools, and questions of the period.
Mathematical contribution
What this hero added or preserved
Core mathematical work
He analyzed cubic equations and studied conditions under which they have positive roots.
Method, teaching, or application
His treatment connected the maximum value of an expression with the number of possible roots.
Why this matters
The larger lesson
Sharaf al-Din al-Tusi shows that mathematics grows through proof, calculation, observation, design, teaching, or careful records. The lasting lesson is that algebra and functions and calculus and change can turn a difficult question into a method another person can inspect and reuse.
Place the work in time
Timeline
- c. 1135
Life and working period
Sharaf al-Din al-Tusi worked as mathematician and astronomer in Persia.
- Legacy
Lasting mathematical connection
His treatment connected the maximum value of an expression with the number of possible roots.
Key idea
An equation balances two descriptions
Sharaf al-Din al-Tusi’s work shows how symbols can represent an unknown quantity while preserving equality.
In 4x + 7 = 15, subtracting 7 and dividing by 4 gives x = 2.
Try it yourself
Solve the equation
Solve 4x + 7 = 15.
- Subtract 7 from both sides.
- Divide both sides by 4.
- Substitute the result to check.
Show the answer
x = 2.
Math at work
Scientists and astronomers use the same habits
Scientists and astronomers use algebra and functions to plan, compare, test, or communicate decisions. Sharaf al-Din al-Tusi’s work provides a historical example of that connection.
Keep curiosity alive
A little-known fact
His treatment connected the maximum value of an expression with the number of possible roots.
Sharaf al-Din al-Tusi matters because of only one famous formula or anecdote.
The documented record is broader: He analyzed cubic equations and studied conditions under which they have positive roots.
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