Let \(R(w) = 2w^2 - w - 2\) with its natural domain.

Completely analyze \(R\).

Domain

\(R\) is a constant linear quadratic function, which means its natural domain is all real numbers.

Zeros

\(R(w)\) doesn’t factor easily. factor. We’ll use the quadratic formula.

\(2w^2 - w - 2 = \)

\(a = \answer {2}\)

\(b = \answer {-1}\)

\(c = \answer {-2}\)

\[ w = \frac {-(-1) \pm \sqrt {(-1)^2 - 4 \cdot 2 \cdot (-2)}}{2 \cdot 2} \]
\[ w = \frac {1 \pm \sqrt {17}}{4} \]

\(R\) has two real zeros.

\[ \frac {1 + \sqrt {17}}{4} \, \text { and } \, \frac {1 - \sqrt {17}}{4} \]
Continuity

\(R\) is a constant linear quadratic function, which means it is continuous.

End-Behavior

The leading coefficient of \(R\) is \(\answer {2}\).

Because \(R\) is a quadratic function with a positive leading coefficient,

\(\lim \limits _{w \to -\infty } R(w) = \answer {\infty }\)

\(\lim \limits _{w \to \infty } R(w) = \answer {\infty }\)

Behavior

The midpoint between \(\frac {1 + \sqrt {17}}{4} \) and \(\frac {1 - \sqrt {17}}{4}\) is \(\frac {1}{4}\).

Because \(R\) is a quadratic function with a positive leading coefficient, \(R\) decreases on \(\left ( \answer {-\infty }, \answer {\frac {1}{4}} \right ]\) and increases on \(\left [ \answer {\frac {1}{4}}, \answer {\infty } \right )\).

Global Extrema

Because \(R\) decreases on \(\left ( -\infty , \frac {1}{4} \right ]\) and increases on \(\left [ \frac {1}{4}, \infty \right )\), \(R\) has a global minimum maximum of \(\answer {-\frac {17}{8}}\) at \(\answer {\frac {1}{4}}\).

Because \(\lim \limits _{w \to \infty } R(w) = \answer {\infty }\), \(R\) has no global minimum maximum.

Local Extrema

The only local minimum value of \(R\) is the global minimum of \(\answer {-\frac {17}{8}}\) at \(\answer {\frac {1}{4}}\).

Range

\(R\) is continuous with no maximum value and a minimum value of \(-\frac {17}{8}\). Therefore, the range of \(R\) is

\[ \left [ \answer {-\frac {17}{8}}, \answer {\infty } \right ) \]
2025-01-07 02:35:42