I/Y = 9.00; FV = 100; N = 10; PMT = 0.11 x 100 = 11; PV = V
0 = 112.84
I/Y = 8.50; FV = 100; N = 10; PMT = 0.11 x 100 = 11; PV = V- = 116.40
I/Y = 9.50; FV = 100; N = 10; PMT = 0.11 x 100 = 11; PV = V+ = 109.42
D = effective duration = [(V- - V+) / (2V0(Δy))]
= (116.40 – 109.42)/(2x112.84x0.005)
= 6.19
