1. The problem asks to find the least frequency, which typically refers to the smallest positive frequency in a given context, such as wave motion or signal processing. 2. Frequency ($f$) is related to the period ($T$) by the formula: $$f = \frac{1}{T}$$ where $T$ is the time period of one complete cycle. 3. To find the least frequency, we need the largest period $T$ because frequency and period are inversely proportional. 4. If the problem provides specific data or context (like harmonics, wave speeds, or lengths), use that to find $T$. 5. Without additional data, the least frequency is the smallest positive value of $f$ that satisfies the system or context. 6. For example, if the fundamental frequency is $f_1$, then the least frequency is $f_1$ itself. 7. Therefore, the least frequency is the fundamental frequency, which is the lowest frequency of vibration or oscillation. Final answer: The least frequency is the fundamental frequency $f_1 = \frac{1}{T_{max}}$ where $T_{max}$ is the maximum period.