Calculus 10th Edition

Published by Brooks Cole
ISBN 10: 1-28505-709-0
ISBN 13: 978-1-28505-709-5

Chapter 3 - Applications of Differentiation - 3.3 Exercises - Page 183: 20

Answer

Critical number: x = -$\frac{2}{3}$ Increasing on (-$\infty$, -$\frac{2}{3}$) Decreasing on (-$\frac{2}{3}$, $\infty$) Relative maximum: (-$\frac{2}{3}$, -$\frac{2}{3}$)

Work Step by Step

f(x) = $-3x^{2}$ -4x-2 f'(x) = -6x-4 0 = -6x-4 Critical number: x = -$\frac{2}{3}$ Intervals: (-$\infty$, -$\frac{2}{3}$) (-$\frac{2}{3}$, $\infty$) Test Values: x = -2, x = 0 x= -2 f'(-2) = -6(-2)-4 f'(-2) = 8 Increasing on (-$\infty$, -$\frac{2}{3}$) x = 0 f'(0) = -6(0) -4 f'(0) = -4 Decreasing on (-$\frac{2}{3}$, $\infty$) f(-$\frac{2}{3}$) = -3 (-$\frac{2}{3})^{2}$ - 4 (-$\frac{2}{3}$) - 2 f(-$\frac{2}{3}$) =-$\frac{2}{3}$ Relative maximum: (-$\frac{2}{3}$, -$\frac{2}{3}$)
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