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MTH-5107 Pretest A Modified. 1. A city whose population was 28000 at the beginning of the century saw its population multiply by 1.1 every 4 years. What exponential expression represents the number of inhabitants (h) of this city as a function of the number of years (t) that have passed?.
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MTH-5107 Pretest A Modified 1. A city whose population was 28000 at the beginning of the century saw its population multiply by 1.1 every 4 years. What exponential expression represents the number of inhabitants (h) of this city as a function of the number of years (t) that have passed? Starting population = a = 28000 c = 1.1 2. Use algebra to solve the following equation. Show all steps in your solution, 2 x – 3 • 8 x + 1 = 32 x - 2 2 x – 3 • (23) x + 1 = (25) x – 2 2 x – 3 • 2 3x + 3 = 25x – 10 2 (x – 3) + (3x + 3) = 25x – 10 24x = 25x – 10 24x = 25x – 10 4x = 5x – 10 -x = -10 x = 10 3. Use algebra to solve the following equation. Show all steps in your solution, 7.5 x + 2 = 3 5x - 1 log 7.5 x + 2 = log 3 5x – 1 (x + 2) log 7.5 = (5x – 1) log 3 x log 7.5 + 2 log 7.5 = 5x log 3 – log 3 x log 7.5 - 5x log 3 = – log 3 - 2 log 7.5 x(log 7.5 – 5 log 3) = – log 3 - 2 log 7.5
4. Find the inverse of the function: f(x) = -3x + 2 y = -3x + 2 3x = -y + 2 Inverse: 3y = -x + 2 y = log3 (-x + 2) f-1(x) = log3 (-x + 2) 5. Given the graph below and the expression of the function, determine the statement below that describes the parameters. f(x) = logc (b(x – h)) • b > 0; 0 < c < 1 and h = 0 • b = 0; c > 1 and h > 0 • b > 0; c > 1 and h < 0 • b > 0; c > 1 and h = 0 • b < 0; 0 < c < 1 and h > 0 • b > 0; 0 < c < 1 and h = 0 • b = 0; c > 1 and h > 0 • b > 0; c > 1 and h < 0 • b > 0; c > 1 and h = 0 • b < 0; 0 < c < 1 and h > 0 Function falls to the right of the asymptote b > 0 Equation of the asymptote is x = 0 h = 0 ab > 0 and function is increasing c > 1
6. Given the graphs below and the expressions of the functions, determine the statement below that describes the parameters of g(x). f(x) = cx g(x) = a•cx + k • a > 0; 0 < c < 1 and k < 0 • 0 < a < 1; c > 1 and k < 0 • a > 1; c > 1 and k < 0 • 0 < a < 1; c > 1 and k > 0 • a > 1; c > 1 and k > 0 Function falls above the asymptote a > 0 Equation of the asymptote is y = -2 k < 0 ab > 0 and function is increasing c > 1 Function g turns more sharply away from asymptote that function f a > 1
The zero is positive. • The y-intercept is 0.75. • It is increasing and c > 1. • It is negative in the interval • Its asymptote is x = 0. 7. Each of the statements below apply to one of the two following functions. State which function applies to each. f(x) g(x) f(x) f(x) f(x) Function f: ab > 0 and c > 1 f is increasing
8. Consider the function below and determine whether the following statements are true or false. If false make them true. True • The zero is positive. • Its domain is x > 1. • Its asymptote is x = 6. • Its range is R. • The y-intercept is 6. True False True False x = h x = 1 Its asymptote is x = 1 2(x – 1) > 0 2x – 2 > 0 2x > 2 x > 1
9. An exponential function passes through the point(-2, 15) and its asymptote is y = -10. Determine the rule of correspondence for this function. y = cx – 10 15 = c-2 – 10 c-2 = 15 + 10 c-2 = 25 c = 5 f(x) = ±cx + k f(x) = cx - 10 k = -10 y1 > k, a is + f(x) = 5x - 10 • You invest $1500 into an annual-interest account, compounded semi-annually. • a) What rule of correspondence determines the balance B(t) as a function of the number of years (t) invested? • b) At what interest rate would this sum double in 6 years? B(t) = 1500•c2t Interest Rate = 1.0595 – 1 = 0.0595 = 5.95% … over half a year 5.95% × 2 = 11.9%
In a lake where fishing is not permitted, 250 lake trout are stocked.. We determine that the population (y) of the trout living in the lake corresponds to the equation below. • a) After 1 year the number of trout is determined to be 300. Determine the value of k. • b) How many years must pass before permitting fishing if a population of 1500 trout are required? Round your answer to the nearest year. k is a constant t is number of years since the lake was stocked y = 250ekt y = 250e0.182t 10 years must pass before fishing is allowed.
12. Determine the value of the following expression given that . 13. Reduce the following logarithmic expression to its simplest form.
14. Circle the letter which corresponds to equivalent of the following expression: 15. Solve for x: b) log3 (2x + 1) + log3 (x – 3) = 2 a) ln(2x + 1) – ln(x – 2) = ln10 Restr#1 2x + 1 > 0 2x > -1 x > -0.5 Restr#1 2x + 1 > 0 2x > -1 x > -0.5 Restr#2 x - 2 > 0 x > 2 Restr#2 x - 3 > 0 x > 3
16. Given the following statements, circle the ones that are false and restate them to make them true. True False False True True