a +1a=3হলে a4+1a4 এর মান কত?
A
49
B
48
C
64
D
47
Correct Answer: 47
a4 + 1a4 = (a2 + 1a2)2 - 2×a2×1a2 = {(a + 1a)2 - 2×a×1a}2 - 2 = {(3)2 - 2}2 - 2 = (9 - 2)2 - 2 = 49 - 2 = 47