A. n(n+1)/2
B. n(n-1)/2
C. (n-1)(n+1)/2
D. n(n+2)/2
Middle term in the expansion of (2x-3/x)15is
If the coefficients of 2nd, 3rd, 4th terms in the expansion of (1+x)2n are in A.P. then
If a is small in comparision with x, then (x/x+a)1/2+( x/x-a)1/2
(√2+1)6+(√2-1)6=
3.C0-5.C1+7.C2-9.C3+…………(n+1) terms =