A graph has month on the x-axis and temperature in degrees Fahrenheit on the y-axis. Month 0 is 23; Month 1 is 35; month 2 is 48; month 3 is 65; month 4 is 74; month 5 is 80; month 6 is 76; month 7 is 64; month 8 is 50; month 9 is 32; month 10 is 24; month 11 is 20. Use the graph to write an equation y = acos[b(x – h)] + k to model the situation.The amplitude is ,