If a+1a=2 , find a4+1a2
4
2
16
8
Given a+1a=2 Squaring on both sides we get (a+1a)2 = (2)2 (a2+1a2+2) = 4 (a2+1a2) = 2 Taking LCM (a2) on the LHS we get a4+1a2 = 2
The least positive integer n such that (2i1+i)n is a positive integer, is
Find the value of ∑∞i=1 ∑∞j=1 ∑∞k=1 12i2j2k.