Data Science Pioneers: Tusi
The great Persian mathematicians
Trigonometry in former science always merged with astronomy. Tusi was the first to write a work on trigonometry independently of astronomy. Tusi, in his Treatise on the Quadrilateral, gave an extensive exposition of spherical trigonometry, distinct from astronomy. It was in the works of Tusi that trigonometry achieved the status of an independent branch of pure mathematics distinct from astronomy, to which it had been linked for so long.
Nasireddin Tusi (Nasir al-Din al-Tusi) was a 13th-century Persian Mathematician who first listed the six distinct cases of a right triangle in spherical trigonometry. He invented the Sine Law for plane triangles.
He also stated the sine law for spherical triangles, discovered the law of tangents for spherical triangles, and provided proof for these laws.
In neural networks, as an alternative to the sigmoid function, the hyperbolic tangent function could be used as an activation function. When we backpropagate, the derivative of the activation function would be involved in the calculation for error effects on weights. The derivative of the hyperbolic tangent function has a simple form just like the sigmoid function.
In February 2013, Google celebrated his 812th birthday with a doodle, which was accessible on its websites in Arabic language calling him al-Farsi (the Persian). His birthday is also celebrated as Engineer’s Day in Iran.
A 60-km diameter lunar crater located on the southern hemisphere of the moon is named after him as “Nasireddin”. A minor planet 10269 Tusi discovered by Soviet astronomer Nikolai Stepanovich Chernykh in 1979 is named after him.
References
Siadati, Saman. (2010). Fundamentals of Mathematics. 10.13140/RG.2.2.31142.75841/1.
