Where is the name “sine” come from

In ancient China, before the introduction of Arabic numerals and variables like x, y, and z, mathematicians used a system based on counting rods and positional notation. They represented unknown quantities using symbols such as 元 (yuan) in the Yuan Dynasty, 天元 (tianyuan), 地元 (diyuan), 人元 (renyuan), and 物元 (wuyuan) in place of x, y, z, and t, respectively.

The expression "x3 + 3x2 + 2x + 6" can be written in English as "x cubed plus 3x squared plus 2x plus 6."

The equation "2x + 6y + 3z + 7t = 0" can be written in English as "Two times x plus six times y plus three times z plus seven times t equals zero."