Since sine and cosine are periodic, our analysis often focuses on the interval \([0, 2\pi )\) and then reasons the remaining information from the periodicity.
  • On \([0, 2\pi )\), the maximum of \(\cos (\theta )\) occurs at \(\answer {0}\).
  • On \([0, 2\pi )\), the minimum of \(\cos (\theta )\) occurs at \(\answer {\pi }\).

If we shift the domain of \(\cos (\theta )\), then the minimum and maximum should follow the shift.

Shifted Domain

Define \(W(m) = \cos \left (m - \frac {\pi }{6} \right )\).

Which interval would we focus on when analyzing \(W(m)\)?

\[ \left [ \answer {\frac {\pi }{6}}, \answer {\frac {7\pi }{6}} \right ) \]

Where does the maximum of \(W(m)\) occur?

\[ m = \answer {\frac {\pi }{6}} \]

Where does the minimum of \(W(m)\) occur?

\[ m = \answer {\frac {7\pi }{6}} \]
2025-05-18 07:04:59