 user25382

In Edo Period, Algebraic equations of three unknown variables were stated in the following expressions.

There exists a right triangle(勾: x 股: y). Now, 勾再自乗数(x^3)と弦再自乗数(弦: hypotenuse z^3)と相井せて共にー百五十二寸(152) (x^3 + z^3 = 152)。股再自乗数(y^3)と弦再自乗数(z^3)と相併せて共にー百八十九寸(y^3 + z^3 = 189)。勾股を問う(What is x, y?)

As for the function, I saw some say one of the concept(ex: hit something into the black box and you get some outcome) was imported into Japan in Edo Period with the word(関数）.

Bonus

Yosh’s answer is very specific. I found japanese mathematician says an American mathematcian used for mathematical symbol.(https://mobile.twitter.com/FumiharuKato/status/860438562415628288) N. KATZ. Nilpotent connections and the monodromy theorem : applications of a result of Turrittin. Publ. math. IHÉS, 39 (1970), p.175-232 user25382

In Edo Period, Algebraic equations of three unknown variables were stated in the following expressions.

There exists a right triangle(勾: x 股: y). Now, 勾再自乗数(x^3)と弦(hypotenuse)再自乗数と弦再自乗数(z弦: hypotenuse z^3)と相井せて共にー百五十二寸(152) (x^3 + yz^3 = 152)。股再自乗数(y^3)と弦再自乗数(z^3)と相併せて共にー百八十九寸(y^3 + z^3 = 189)。勾股を問う(What is x, y?)

As for the function, I saw some say one of the concept(ex: hit something into the black box and you get some outcome) was imported into Japan in Edo Period with the word(関数）. user25382