If `a_1,a_2,a_3 and a_4` be any four consecutive coefficients in the expansion of `(1+x)^n`, prove that `a_1/(a_1+a_2)+a_3/(a_3+a_4)= (2a_2)/(a_2+a_3)`

If a_0,a_1,a_2,……a_n be the successive coefficients in the expnsion of (1+x)^n show that (a_0-a_2+a_4……..)^2+(a_1-a_3+a_5………)^2=a_0+a_1+a_2+………..+a_n=2^n

If 1, a_1,a_2,a_3 ,…, a_(n-1) are the nth roots of unity then prove that : (1-a_1)(1-a_2)(1-a_3)...(1-a_(n-1)) =n.

If a_i>0, i=1, 2, 3,..., n then prove that a_1/a_2+a_2/a_3+a_3/a_4+...+a_(n-1)/a_n+a_n/a_1gen .

If a_1, a_2, a_3,...a_20 are A.M's inserted between 13 and 67 then the maximum value of the product a_1 a_2 a_3...a_20 is

Prove that ((a_1)/(a_2)+(a_3)/(a_4)+(a_5)/(a_6)) ((a_2)/(a_1)+(a_4)/(a_3)+(a_6)/(a_5)) geq 9

If a_1,a_2,a_3,.....,a_n are in AP where a_i ne kpi for all i , prove that cosec a_1* cosec a_2+ cosec a_2* cosec a_3+...+ cosec a_(n-1)* cosec a_n=(cota_1-cota_n)/(sin(a_2-a_1)) .

If a_1, a_2, a_3, .... a_4001 are terms of an A.P. such that 1/(a_1a_2)+1/(a_2a_3)+1/(a_3a_4)+......1/(a_4000a_4001)=10 and a_2+a_4000=50, then |a_1-a_4001| is equal to