<p>Exponential Functions Worksheet Answers</p><p>Graph the functions</p><p>1. f (x)  4 x</p><p> x y - 3 0.015 - 2 0.063 - 1 0.25 0 1 1 4 2 16 3 64</p><p>2. f x  0.5 x</p><p> x y - 3 8 - 2 4 - 1 2 0 1 1 0.5 2 0.25 3 0.13 3. f x  1.25 x</p><p> x y - 3 0.512 - 2 0.64 - 1 0.8 0 1 1 1.25 2 1.563 3 1.953</p><p> x 4. f (x)  2 2</p><p> x y - 3 0.354 - 2 0.5 - 1 0.707 0 1 1 1.414 2 2 3 2.828 5. If you invest $25,000 in an account that gets 12% annual interest compounded quarterly, how much would you have in 10 years.</p><p>P = 25000, r = 0.12/4 = 0.03, t = 10 x 4 = 40</p><p>A  P1 rt A  250001 0.0340 A  250001.0340 A  250003.262 A  81550.94</p><p>6. If you invested a penny on Jan 1, 1776 at 10% interest compounded daily, how much would you have on Jan 1, 2011 ?</p><p>P = 0.01, r = 0.10/365 = 0.00027, t =( 2011 – 1776 ) x 365 = 85775</p><p>A  0.011 0.0002785775 A  0.011.0002785775 A  0.01(11,391,394,790) A 113,913,947.90</p><p>7. How much would you need to invest to get $20,000 in 5 years at an annual interest rate of 8.5% compounded monthly ?</p><p>A = 20,000, r = 0.085/12 = 0.007, t = 5 x 12 = 60</p><p>20000  P1 0.00760 20000  P1.00760 20000  P1.52 13157.89  P 8. The half - life of Barium-137m is 2.552 minutes. How much of an 18 gram sample would be left after 10 minutes</p><p>10 M (18) 180.5 2.552 M (18) 18(0.5)3.918 M (18) 180.0662 M (18) 1.191g</p><p>9. The half – life of carbon 14 is 5,730 years. How much of a 50 gram sample would be left after 15,000 years ?</p><p>15000 M (50)  500.5 5730 M (50)  500.52.618 M (50)  500.163 M (50)  8.145g</p><p>10. The half – life of Strontium – 85 is 64.84 days. How much of a 40 mg sample would be left after 180 days ?</p><p>180 M (40)  400.564.84 M (40)  400.52.776 M (40)  400.146 M (40)  5.84mg</p>