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

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

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

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 a_iepsilon R-[0},i=1,2,3,4 and xepsilon R and (sum_(i=1)^ a_i^2) x^2-2x(sum_(i=)^3 a_ia_(i+1)+)+sum_(i=2)^4 a_i^2ge0 then a_1,a_2,a_3,a_4 are in (A) A.P. (B) G.P. (C) H.P. (D) none of these

If sum_(i=1)^(18)(x_(i) - 8) = 9 and sum_(i=1)^(18)(x_(i) - 8)^(2) = 45 then find the standard deviation of x_(1), x_(2),….x_(18)

If sum_(i=1)^n(x_i+1)^2=9n and sum_(i=1)^n(x_i-1)^2=5n , then standard deviation of these 'n' observations (x_1) is: (1) 2sqrt(3) (2) sqrt(3) (3) sqrt(5) (4) 3sqrt(2)

If x+i y=(1+i)(1+2i)(1+3i),\ t h e n\ x^2+y^2 is: (a) . 0 (b) . 1 (c) . 100 (d) . none of these

If sum_(i=1)^(5) (x_(i) - 6) = 5 and sum_(i=1)^(5)(x_(i)-6)^(2) = 25 , then the standard deviation of observations

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 x_i gt 0 for 1leilen and x_1+x_2+x_3+…+x_n=pi then the greatest value of the sum sinx_1+sinx_2+sinx_3+…+sin_n=… (A) n (B) pi (C) nsin\ pi/n (D) none of these