If `1 + a + a^(2) + a^(3) + ... + a^(n) = (1+a)(1+a^(2))` then `n` is equal to :
(a) 3
(b) 5
(c) 7
(d) 9

(2^(-1)+3^(-1)+5^(-1))^(0) is equal to (a) 2 (b) 3 (c) 5 (d) 1

5 n+2 −6 xx 5 n+113 xx 5 n − 2 5 n+1 is equal to (a) 5 3 (b) − 5 3 (c) 3 5 (d) − 3 5

If A=[(2,3),(5,-2)] then 9A^-1 is equal to (A) A\' (B) 2A (C) 1/2 A (D) A

If 2^(n+4)-2^(n+2)=3, then n is equal to a.0 b.2c.-2d.-1

1+3/2+5/2^2+7/2^3+……..to oo is equal to (A) 3 (B) 6 (C) 9 (D) 12

If (1-tan^(2)36^(@))/(2)=sqrt(a)-sqrt(b) ,then the value of (a+b) is equal to (a,b in N) (A)5 (B) 9 (C) 7 (D)None of these

If sum_(n=1)^(5)(1)/(n(n+1)(n+2)(n+3))=(k)/(3), then k is equal to :-

If ^(n+1)C_3=2.^nC_2, then n= (A) 3 (B) 4 (C) 5 (D) 6