The approximate value of (7.995)13 correct to four decimal places is
1.9995
(7.995)13 = (8−0.005)13 = (8)13 [1−0.0058]13
= 2[1 - 13 × 0.0058 + 13(13−1)2+1 (0.0058)2 + ............]
= 2[1 - 0.00524 - 13×131 × \(\frac{(0.005)^2}{8} + ......... ]\)
=2(1−0.000208)=2×0.999792=1.9995