If `sum_(i=1)^200 sin^-1 x_i=100pi, then sum _(i=1)^200 x_i^2` is equal to

If sum_(i=1)^10 sin^-1 x_i = 5pi then sum_(i=1)^10 x_i^2 = (A) 0 (B) 5 (C) 10 (D) none of these

sum_(i=1)^(n) sum_(i=1)^(n) i is equal to

The standard deviation of n observations x_(1), x_(2), x_(3),…x_(n) is 2. If sum_(i=1)^(n) x_(i)^(2) = 100 and sum_(i=1)^(n) x_(i) = 20 show the values of n are 5 or 20

If sum_(r=1)^n I(r)=(3^n -1) , then sum_(r=1)^n 1/(I(r)) is equal to :

Let x_(1),x_(2),x_(3), . . .,x_(k) be the divisors of positive integer ' n ' (including 1 and x ). If x_(1)+x_(2)+ . . .+x_(k)=75 , then sum_(i=1)^(k)(1)/(x_(i)) is equal to:

sum_(i=1)^(2n) sin^(-1)(x_i)=npi then the value of sum_(i=1)^n cos^(-1)x_i+sum_(i=1)^n tan^(-1)x_i= (A) (npi)/4 (B) (2/3)npi (C) (5/4)npi (D) 2npi

If n= 10, sum_(i=1)^(10) x_(i) = 60 and sum_(i=1)^(10) x_(i)^(2) = 1000 then find s.d.

If x_1,x_2,.......,x_n are n values of a variable X such that sum_(i=1)^n (x_i-2)=110 and sum_(i=1)^n(x_i-5) =20 . Find the value of n and the mean.

If sum_(i=1)^(7) i^(2)x_(i) = 1 and sum_(i=1)^(7)(i+1)^(2) x_(i) = 12 and sum_(i=1)^(7)(i+2)^(2)x_(i) = 123 then find the value of sum_(i=1)^(7)(i+3)^(2)x_(i)"____"

If x_1, x_2, .....x_n are n observations such that sum_(i=1)^n (x_i)^2=400 and sum_(i=1)^n x_i=100 then possible values of n among the following is