MIDTERM REVIEW 2 SUMMER KEY.pdf - MATH1231(Summer 1 2020...

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1 MATH1231(Summer 1 2020) Midterm Exam Name_______________ Instructor: Dr. R. Bai(Total points = 50) You must show all work in order to get credit. 1.The following table gives United States coal consumption (in millions of short tons), t years since 1950: Year 0 10 20 30 35 40 45 Coal consumption 494.1 398.1 523.2 702.7 818 895.5 962 1005.6 a)(6 points)Let C(t) denote the coal consumption in United States where t denotes number of years since 1950. Use the table to find the best fit model for C(t), choosing from exponential, quadratic, cubic or logistic model. Round all coefficients to 3 decimal places and include units. b)(4 points)According to the full model, what was the percentage change in coal consumption between 1970 and 1980? (Give your answer rounded to 2 decimal places. Give units.) 2.(4 points)The function ?gives a person’s weight in pounds 𝑡weeks after she begins a diet. Write a sentence of interpretation for ?(8) = −146 47 1027.1
2 3.(8 points each)Find the derivative of each function. Show as much work as possible. Do not simplify your answer.