37 ERROR ANALYSIS You invest 500 in the stock of a Acompany The value of the stock decreases 2 each year Describe and correct the error in writing a model for the value of the stock after years y Decay Initial amount factor y 500 0 02 41 r 1 26 compounded monthly In Exercises 39 42 use the given information to find the balance in the account earning compound interest after 6 years when the principal is 3500 39 r 2 16 compounded quarterly 5 MTR 43 STRUCTURE In the compound interest formula for interest compounded yearly A P 1 r what does P represent What does 1 r represent Does P depend on 1 r Does 1 r depend on P Explain 5 COMPARING FUNCTIONS Compare the graph of f x 2 1 5 to the graph of g Which graph has a greater y intercept Which graph is increasing at a faster rate Explain your reasoning 4 2 Ay 2 g 38 ERROR ANALYSIS You deposit 250 in an account that pays 1 25 annual interest Describe and correct the error in finding the balance after 3 years when the interest is compounded quarterly X 4 X 14 3 A 250 1 1 25 1 5 6533 29 40 r 2 29 compounded monthly 42 r 1 83 compounded daily MTR 5 44 STRUCTURE The equation y 1000 1 12 represents the balance y in dollars in an account after t years a What is the annual interest rate Explain b Rewrite the function in the form y 1000b 2r c Explain how you can use your equation in part b to find the monthly interest rate 46 HOW DO YOU SEE IT Chapter 6 Exponential and Logarithmic Functions The graph shows an exponential function of the form f x abx a Determine whether frepresents exponential growth or exponential decay 1 4 0 1 1 4 2 6 b What are the domain and range of the function Explain