The sequence `{b_n }` is a geometric progression with `b_4/b_6=1/4 and b_2+b_5=216.` If `b_n in I AA n in N,` then the value of `b_1` is (i)`8` (ii)`10` (iii)`12` (iv)`14`

If n(A nn B')=5 ,n(B nn A')=6 ,n(A nn B)=4 then the value of n(A uu B) is

If n (xi)=50,n((AuuB)')=15,n=(A-B)=12 and n(B-A)=14 , then n(AnnB) is (i) 9 (ii) 10 (iii) 11 (iv) 12

If a=3\ \ a n d\ b=-2\ , find the values of: (i)\ a^a+b^b (ii)\ a^b+b^a (iii)\ (a+b)^(a b)

If n (A-B)=10, n(B-A)=23, n(AuuB)=50 , then n(AnnB) is (i) 7 (ii) 17 (iii) 27 (iv) 33

If ? is an operation on integers such that for integers a\ a n d\ b ,\a? b=a-b-(-5) Find the value of (i) (-7)?3 (ii) (-9)? (-4) (iii) 2? 5 (iv) 4? (-5)

Let a_(1),a_(2),a_(3)"……." be an arithmetic progression and b_(1), b_(2), b_(3), "……." be a geometric progression sequence c_(1),c_(2),c_(3,"…." is such that c_(n)= a_(n) + b_(n) AA n in N . Suppose c_(1) = 1, c_(2) = 4, c_(3) = 15 and c_(4) = 2 . The value of sum of sum_(i = 1)^(20) a_(i) is equal to "(a) 480 (b) 770 (c) 960 (d) 1040"

If the geometric mean of a and b is (a^(n+1)+b^(n+1))/(a^(n)+b^(n)) then n = ?

If the geometric mean of a and b is (a^(n+1)+b^(n+1))/(a^(n)+b^(n)) then n = ?

The sequence a_(1),a_(2),a_(3),".......," is a geometric sequence with common ratio r. The sequence b_(1),b_(2),b_(3),".......," is also a geometric sequence. If b_(1)=1,b_(2)=root4(7)-root4(28)+1,a_(1)=root4(28)" and "sum_(n=1)^(oo)(1)/(a_(n))=sum_(n=1)^(oo)(1)/(b_(n)) , then the value of (1+r^(2)+r^(4)) is