\( 1<\quad \begin{array}{l}\text { Find the range of the quadratic function and the maximum or minimum value of the function. Identify the intervals over } \\ \text { which the function is increasing or decreasing. } \\ y=2 x^{2}+5 x+3\end{array} \)
Solución de inteligencia artificial de Upstudy
Responder
Solución
Respondido por UpStudy AI y revisado por un tutor profesional


Beyond the Answer
To find the range of the quadratic function \( y = 2x^2 + 5x + 3 \), we first determine whether it opens upwards or downwards. Since the coefficient of \( x^2 \) is positive (2), the parabola opens upwards, indicating that it has a minimum value. We can find this minimum using the vertex formula \( x = -\frac{b}{2a} \). For our function, \( a = 2 \) and \( b = 5 \), so \( x = -\frac{5}{2(2)} = -\frac{5}{4} \). Substituting this back into the function gives us the minimum value: \[ y = 2\left(-\frac{5}{4}\right)^2 + 5\left(-\frac{5}{4}\right) + 3 = 2\left(\frac{25}{16}\right) - \frac{25}{4} + 3 = \frac{25}{8} - \frac{50}{8} + \frac{24}{8} = -\frac{1}{8} \] Thus, the minimum value is \( -\frac{1}{8} \). Since the parabola opens upwards, the range of the function is \( \left[-\frac{1}{8}, \infty\right) \). To determine where the function is increasing or decreasing, we find the derivative \( y' = 4x + 5 \). Setting this to zero to find critical points gives \( 4x + 5 = 0 \Rightarrow x = -\frac{5}{4} \). The function decreases for \( x < -\frac{5}{4} \) and increases for \( x > -\frac{5}{4} \). Thus, the intervals are: - Decreasing: \( (-\infty, -\frac{5}{4}) \) - Increasing: \( (-\frac{5}{4}, \infty) \)
