Question

If ∑cos^-1x_i for i∈[i=1, 10] = 0, then ∑x_i for i∈[i=1, 10] is

(A) 0

(B) 10

(C) 5 

(D) None of these 

Answer 1

Correct option (B) 10

Explanation:

Since, cos^-1x² has to be zero separately, only the

 

Adding all the terms, we get