consider the following. (if an answer does not exist, enter dne.) f(x)=2x³ - 15x² + 36x - 6 (a) find the…

consider the following. (if an answer does not exist, enter dne.) f(x)=2x³ - 15x² + 36x - 6 (a) find the interval(s) on which f is increasing. (enter your answer using interval notation.) (b) find the interval(s) on which f is decreasing. (enter your answer using interval notation.) (c) find the local minimum and maximum value of f. local minimum value local maximum value

consider the following. (if an answer does not exist, enter dne.) f(x)=2x³ - 15x² + 36x - 6 (a) find the interval(s) on which f is increasing. (enter your answer using interval notation.) (b) find the interval(s) on which f is decreasing. (enter your answer using interval notation.) (c) find the local minimum and maximum value of f. local minimum value local maximum value

Answer

Explanation:

Step1: Find the derivative of (f(x))

Differentiate (f(x)=2x^{3}-15x^{2}+36x - 6) using the power - rule ((x^n)^\prime=nx^{n - 1}). (f^\prime(x)=6x^{2}-30x + 36)

Step2: Set (f^\prime(x)=0) to find critical points

Factor out 6 from (f^\prime(x)): (f^\prime(x)=6(x^{2}-5x + 6)). Set (x^{2}-5x + 6 = 0), factor the quadratic equation: ((x - 2)(x - 3)=0). The critical points are (x = 2) and (x=3).

Step3: Test the intervals determined by the critical points

Choose test points in the intervals ((-\infty,2)), ((2,3)) and ((3,\infty)). For the interval ((-\infty,2)), let (x = 1). Then (f^\prime(1)=6(1 - 5+6)=12>0). For the interval ((2,3)), let (x = 2.5). Then (f^\prime(2.5)=6(6.25-12.5 + 6)=6\times(-0.25)<0). For the interval ((3,\infty)), let (x = 4). Then (f^\prime(4)=6(16 - 20+6)=12>0).

Step4: Determine increasing and decreasing intervals

Since (f^\prime(x)>0) on ((-\infty,2)\cup(3,\infty)), (f(x)) is increasing on ((-\infty,2)\cup(3,\infty)). Since (f^\prime(x)<0) on ((2,3)), (f(x)) is decreasing on ((2,3)).

Step5: Find local minimum and maximum values

Evaluate (f(x)) at the critical points. (f(2)=2\times2^{3}-15\times2^{2}+36\times2 - 6=16-60 + 72-6=22). (f(3)=2\times3^{3}-15\times3^{2}+36\times3 - 6=54-135 + 108-6=21). Since (f(x)) changes from increasing to decreasing at (x = 2), (f(2)=22) is a local maximum. Since (f(x)) changes from decreasing to increasing at (x = 3), (f(3)=21) is a local minimum.

Answer:

(a) ((-\infty,2)\cup(3,\infty)) (b) ((2,3)) (c) local minimum value: (21) local maximum value: (22)