1. provide an appropriate response.
a company estimates that it will sell n(t) hair dryers after spending $t thousands on advertising as given by:
n(t) = -3t3 + 450t2 - 21,600t + 1,100, 40 ? t ? 60 for which values of t is the rate of sales n'(t) increasing?
a. 50 < t < 60 b. 40 < t < 50. c. t > 40 d. 40< t < 60

D. 40 < t < 60

Step-by-step explanation:

Given function,

Differentiating with respect to x,

For increasing or decreasing,

f'(x) = 0,

By the quadratic formula,

Since, in the interval -∞ < t < 40, f'(x) = negative,

In the interval 40 < t < 60, f'(t) = Positive,

While in the interval 60 < t < ∞, f'(t) = negative,

Hence, the values of t for which N'(t) increasing are,

40 < t < 60,

Option 'D' is correct.

d

step-by-step explanation:

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step-by-step explanation: