Let `a_n, n in N` is an A.P with common difference `d` and all whose terms are non-zero. If n approaches infinity, then the sum `1/(a_1a_2)+1/(a_2a_3)+....1/(a_na_(n+1))` will approach

Let a_(n),n in N is an A.P with common difference d and all whose terms are non-zero. If n approaches infinity,then the sum (1)/(a_(1)a_(2))+(1)/(a_(2)a_(3))+...(.1)/(a_(n)a_(n+1)) will approach

If a_1,a_2,a_3,...,a_(n+1) are in A.P. , then 1/(a_1a_2)+1/(a_2a_3)....+1/(a_na_(n+1)) is

Write the common difference of an A.P. whose n t h term is a_n=3n+7 .

If a_1, a_2,a_3, ,a_n is an A.P. with common difference d , then prove that "tan"[tan^(-1)(d/(1+a_1a_2))+tan^(-1)(d/(1+a_2a_3))+tan^(-1)(d/(1+a_(n-1)a_n))]=((n-1)d)/(1+a_1a_n)

If a_1, a_2,a_3, ,a_n is an A.P. with common difference d , then prove that "tan"[tan^(-1)(d/(1+a_1a_2))+tan^(-1)(d/(1+a_2a_3))+......+tan^(-1)(d/(1+a_(n-1)a_n))]=((n-1)d)/(1+a_1a_n)

If a_1,a_2,.....a_n are in H.P., then the expression a_1a_2 + a_2a_3 + ... + a_(n-1)a_n is equal to

Write the common difference of an A.P. the sum of whose first \ \ n terms is P/2n^2+Q n

If a_1,a_2,a_3, ,a_n are an A.P. of non-zero terms, prove that 1/(a_1a_2)+1/(a_2a_3)++1/(a_(n-1)a_n)= (n-1)/(a_1a_n)

If a_1, a_2,a_3, ,a_n is an A.P. with common difference d , then "tan"[tan^(-1)(d/(1+a_1a_2))+tan^(-1)(d/(1+a_2a_3))+...+tan^(-1)(d/(1+a_(n-1)a_n))]=