The part of maths that studies triangles — specifically, how the angles of a triangle and the lengths of its sides are tied to each other. If you know some of them, trigonometry lets you work out the rest. That is why it is not just school homework: it is how people measure a mountain they cannot climb, how a ship finds its position, how a phone works out where you are, and how computers draw anything that moves.

The part of maths that studies triangles數學裡研究三角形的那個部分 — specifically, how the angles of a triangle and the lengths of its sides are tied to each other確切來說，是三角形的角度和邊長之間怎麼互相對應。 If you know some of them只要你知道其中一部分, trigonometry lets you work out the resttrigonometry 就能讓你算出剩下的部分。 That is why it is not just school homework這就是為什麼它不只是學校作業: it is how people measure a mountain they cannot climb人們就是靠它測量爬不上去的山, how a ship finds its position靠它讓船找出自己的位置, how a phone works out where you are讓手機算出你在哪裡, and how computers draw anything that moves還有讓電腦畫出任何會動的東西。

Its famous words are sine, cosine and tangent, usually written sin, cos, tan. It is an uncountable noun, so no 'a' and no plural: you study trigonometry, you have a trigonometry test.

Its famous words are sine, cosine and tangent它最有名的幾個詞是 sine（正弦）、cosine（餘弦）、tangent（正切）, usually written sin, cos, tan通常寫成 sin、cos、tan。 It is an uncountable noun, so no 'a' and no plural它是不可數名詞，不加 a，也沒有複數: you study trigonometry可以說 you study trigonometry, you have a trigonometry test、you have a trigonometry test。

In everyday speech almost nobody says the whole word — students say trig, which rhymes with 'big'. The adjective is trigonometric (a trigonometric function). Say it try-guh-NOM-uh-tree: five beats, with the stress on NOM.

In everyday speech almost nobody says the whole word日常口語裡幾乎沒有人講完整這個字 — students say trig, which rhymes with 'big'學生會說 trig，跟 big 押韻。 The adjective is trigonometric形容詞是 trigonometric (a trigonometric function)（例如 a trigonometric function，三角函數）。 Say it try-guh-NOM-uh-tree念法是 try-guh-NOM-uh-tree: five beats, with the stress on NOM五個音節，重音在 NOM 上。