正弦

1. Origins, structure, and basic meaning

• Structure: 正弦 is read as せいげん and is a mathematical noun for the sine of an angle or the function underlying a sine form.
• Basic usage: Use 角度の正弦 for a value and the compound 正弦波 for a waveform.

2. Common pitfalls and similar expressions

• Value and waveform
  • 正弦を計算する obtains a numerical value for an angle, while 正弦波の信号 names a signal that varies in sine-wave form.
• Scope of the compound
  • 正弦波 is a complete technical compound, so 正弦 alone should not automatically be treated as the wave itself.