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h(x)=1/8x^3-x^2

Over which interval does h have a positive average rate of change?

Respuesta :

Answer:

[tex](-\infty,0)\cup(\frac{16}{3},\infty)\\That \ is x<0 \ or \ x>\frac{16}{3}[/tex]

Step-by-step explanation:

[tex]h(x)=\frac{1}{8}x^{3} -x^{2} \\\\Differentiate \ h(x) \ with \  respect \ to \ x\\h'(x)=\frac{3}{8}x^{2} -2x[/tex]

For positive rate of change [tex]h'(x)>0[/tex]

[tex]\frac{3}{8} x^{2} -2x>0\\x(\frac{3}{8}x-2)>0\\\\ When \ x<0 \Rightarrow (\frac{3}{8}x-2)<0 \Rightarrow h'(x)>0 \ (multiplication \ of \ two \ negative \ gives \ positive)\\\\When (\frac{3}{8}x-2)>0 \Rightarrow x>\frac{16}{3} \Rightarrow x>0\\\\h'(x)=x(\frac{3}{8}x-2) >0 \ (multiplication \ of \ two \ positives \ is \ positive)\\\\h'(x)>0 \ when \ x<0 \ or \ x>\frac{16}{3} \\\\[/tex]

Answer: 6 < x < 8

Step-by-step explanation: