θ（シーター）って英語でなんて言うの？

「θ（シーター）」はギリシャ文字で、英語では"theta"と言います。数学ではどこの国に勉強してもギリシャ文字が頻繁に使われているので、ある程度知った方がいいかもしれません。
α　Alpha
β　Beta
γ　Gamma
δ　Delta（Δのようにも書く場合も多いです。）
ε　Epsilon
σ　Sigma（和を表す時は一般的に∑と書きます。）
ω　Omega（Ωのようにも書く場合があります）
などがあります。

参考になれば幸いです。

ご質問ありがとうございます。

英語でも「シータ」と呼びます。
スペルは、Thetaとなります。
発音は少し難しく、thの発音になりますので、舌を上下の前の歯で軽く噛むような形にして、シィータと発音してみて下さい。

ちなみに、サインコサインなども英語でそのままになりますよ！

ご参考になりましたら幸いです。

Context is EVERYTHING IN ENGLISH...We must avoid looking at any word in isolation for each and every word, truly depends on its neighbours to elicit clarity of meaning!
In this case, θ may signify a number of things in is, in essence, a symbol;-)
It may well be "Theta" or indeed the "Th"... in thing" The Voiceless dental fricative;-)
As I mentioned. context is everything:-)

This is a Greek letter - or a phonemic symbol for the 'th' sound in THING. Greek letters are not usually relevant in English. However, for example, with β Beta, the word Beta is frequently used when testing a new product - especially a software product these days. So any product in its 'beta stage' is undergoing a trial or experimental period of some kind before a general release.

We call that symbol after the Greek letter "Theta" (pronounced THEI-tah). We use the Theta symbol whenever we are trying to calculate an unknown angle. It is also commonly used in trigonometric ratios with sines (SIN), cosines (COS), and tangents (TAN). In those latter cases Theta is calculated by dividing the lengths of the sides and calculating the resulting trignonometric ratio.

This symbol that is primarily used in mathematics is called the, "theta," symbol. This originally comes from a greek letter and then later on it was adapted to be used in math. This isn't so much a word we would use in everyday conversation but rather in just the math world.

A theta is a Greek symbol and it can be used for many things.

Example;
- To solve this question you have to use the theta function.
- Find the value of the theta symbol in the equation.