In a G.P. `a = 81, r = -1/3, a_(3) = ……….`

Write the G.P . If a = 81, r = (-1)/3

If for a G.P., t_3 = 1/3 , t_6 = 1/81 , find r.

Write three terms of the G.P. when the first term 'a' and the common ratio 'r' are given. (iii) a = 81, r = -1/3 .

The successive terms of an A.P. are a_(1), a_(2), a_(3) ,….. If a_(6)+a_(9)+a_(12)+a_(15)=20 then sum_(r=1)^(20)a_(r) =

For an increasing G.P. a_(1), a_(2), a_(3),.....a_(n), " If " a_(6) = 4a_(4), a_(9) - a_(7) = 192 , then the value of sum_(l=1)^(oo) (1)/(a_(i)) is

For an increasing G.P. a_(1), a_(2), a_(3),.....a_(n), " If " a_(6) = 4a_(4), a_(9) - a_(7) = 192 , then the value of sum_(l=1)^(oo) (1)/(a_(i)) is

Consider an A.P. a_(1), a_(2), "……"a_(n), "……." and the G.P. b_(1),b_(2)"…..", b_(n),"….." such that a_(1) = b_(1)= 1, a_(9) = b_(9) and sum_(r=1)^(9) a_(r) = 369 , then