3 sentences

1. 在数学公式中，我们常用希腊字母套来表示常数。

   zài shù​xué gōng​shì zhōng, wǒ​men cháng​yòng Xī​là zì​mǔ tào lái biǎo​shì cháng​shù.

   In mathematical formulas, we often use the Greek letter tau to represent constants.

   Source: Dong Chinese Dictionary

2. 在复杂的公式变换过程中，这个常数始终保持不变。

   zài fù​zá de gōng​shì biàn​huàn guò​chéng zhōng, zhè​ge cháng​shù shǐ​zhōng bǎo​chí bù​biàn.

   During the complex transformation of the formula, this constant stays the same.

   Source: Dong Chinese Dictionary

3. 在物理学计算中，我们通常用卡帕来代表这个常数。

   zài wù​lǐ​xué jì​suàn zhōng, wǒ​men tōng​cháng yòng kǎ​pà lái dài​biǎo zhè​ge cháng​shù.

   In physics calculations, we usually use kappa to represent this constant.

   Source: Dong Chinese Dictionary