let `a_1,a_2,...a_n` be in A.P. wth common difference `pi/6`. If `seca_1seca_2+seca_2seca_3+....seca_(n-1)seca_n`=`k(tana_n-tana_1). ` Find the value of k

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

The sum of n terms of an A.P is n^2 .Find the common difference.

If a_1,a_2,a3,...,a_n are in A.P then show that 1/(a_1a_2)+1/(a_2a_3)+1/(a_3a_4)+...+1/(a_(n-1)a_n)=(n-1)/(a_1a_n)

If "^(2n+1)P_(n-1):^(2n-1)P_n=3:5, then find the value of n .

If a_1,a_2,a_3,.......a_n are in AP where a_1 gt 0foralli then the value of 1/(sqrta_1+sqrta_2)+1/(sqrta_2+sqrta_3)+....1/(sqrta_(n-1)+sqrta_n=

If secA+tanA=3/2 then

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 >0, then prove that (a_1)/(a_2)+(a_2)/(a_3)+(a_3)/(a_4)+.....+(a_(n-1))/(a_n)+(a_n)/(a_1)> n

The sum to n terms of an A.P. is n^(2) . Find the common difference.

Let vec r_1, vec r_2, vec r_3, .....vec r_n be the position vectors of points P_1,P_2, P_3 ,......P_n relative to the origin O . If the vector equation a_1 vec r_1+a_2 vec r_2+.....a_n vec r_n=0 hold, then a similar equation will also hold w.r.t. to any other origin provided a) a_1+a_2+......a_n=n b) a_1+a_2+....a_n=1 c) a_1+a_2+....a_n=0 d) a_1=a_2=a_3+a_n=0