Hi I need help with questions 7, 13, and 14 please.
10:38 D a webassign.net Relative minima: X = DNE Need Help? Watch It 12. [1/1 Points] DETAILS PREVIOUS ANSWERS TANAPMATH7 10.1.084.NVA MY NOTES ASK YOUR TEACHER Almost half of companies let other firms manage some of their Web operations - a practice called Web hosting. Managed services - monitoring a customer's technology services - is the fastest growing part of Web hosting. Managed services sales are approximated by the function f(t) = 0.469t2 + 0.758t + 0.44 (0 s t s 10) where f(t) is measured in billions of dollars and t is measured in years, with t = 0 corresponding to 1999.+ (a) Find the interval where f is increasing. (Enter your answer using interval notation.) (0,10) (b) What does your result tell you about sales in managed services from 1999 through 2009? Sales remained the same during this period. Sales were increasing during this period. In 1999 sales were much bigger than in 2009. Sales were decreasing during this period. Sales were initially increasing, but then became constant. 13. [0.5/1 Points] DETAILS PREVIOUS ANSWERS TANAPMATH7 10.1.085. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Following the lead of the National Wildlife Federation, the Department of the Interior of a South American country began to record an index of environmental quality that measured progress and decline in the environmental quality of its forests. The index for the years 2004 through 2014 is approximated by the function I(t) = -+3 - 3+2 + 80 (0 s t s 10) where t = 0 corresponds to 2004. Find the intervals where the function I is increasing and the intervals where it is decreasing. (Enter your answers using interval notation.) increasing (0,5) X decreasing (5,10) X Interpret your results. After initially | declining , the index increases Need Help? Read It 14. [-/1 Points] DETAILS TANAPMATH7 10.1.091.NVA MY NOTES ASK YOUR TEACHER A study of driving costs based on 2012 medium-sized sedans found that the average cost (car payments, gas, insurance, upkeep, and depreciation) in cents per mile is approximately C(x) = 1910.2 + 42.9 (5 5 x s 20) x1.72 where x (in thousands) denotes the number of miles the car is driven each year. Show that C is a decreasing function of x on the interval (5, 20). 2 . . .10:38 D webassign.net 100 000 -0.06 2000 4000 6000 8000 10 000 12 000 -0.08 Need Help? Watch It 5. [1.33/1.33 Points] DETAILS PREVIOUS ANSWERS TANAPMATH7 9.8.017.MI.NVA MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The quantity of Sensitech laser gaming mice demanded each month is related to the unit price by the equation 48 P = (0 S x S 20) 0.05x2 + 1 where p is measured in thousands of dollars and x in units of a thousand. (a) Find the revenue function R. 48x R(X ) = 0.05x-+ 1 (b) Find the marginal revenue function R'. -2.4x2 + 48 R' ( X ) = 0.05x2 + 1)2 (c) Compute R'(2). (Round your answer to three decimal places.) R'(2) = 26.667 Need Help? Master It 6. [1/1 Points] DETAILS PREVIOUS ANSWERS TANAPMATH7 9.8.027.NVA MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Find the percentage rate of change of f at the given value of x. (Round your answer to two decimal places.) f ( x ) = 3 x+1 x3 +x+1' fix = 3 -65.32 percent per unit change in x 7. [0/1 Points] DETAILS PREVIOUS ANSWERS TANAPMATH7 9.8.028.NVA MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Find the percentage rate of change of f at the given value of x. (Round your answer to three decimal places.) F(x ) = ( X z/E ;x = 1 87.17 * percent per unit change in x 8. [1/1 Points] DETAILS PREVIOUS ANSWERS TANAPMATH7 9.8.029.NVA MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The consumer price index (CPI) of a certain country is given by I(t) = -0.02t3 + 0.42 + 125 (0 s t s 4) where t = 0 corresponds to the beginning of 2013. Find the annual percentage rate of inflation in the CPI of the country at the beginning of 2015. (Round your answer to three decimal places.) 1.076 %/year + 2
