Domain of f(x) = cos-1x + cot-1x+ cosec-1x is
A [-1,1] B R C (-INFINITY,-1]U[1,INFINITY) D {-1,1}
ANswer is D. EXPLAIN PLEASE!
Domain of cos-1x = [-1 ,1]
Domain of cot-1x = R
Domain of cosec-1x = R - (-1,1)
So taking intersection of domains of all three we have only {-1 ,1}
As cos-1x is confined between [-1,1] and cosec-1x is not defined between (-1,1) , so only -1 and 1 are left.
So option D is correct .
Domain of cot-1x = R
Domain of cosec-1x = R - (-1,1)
So taking intersection of domains of all three we have only {-1 ,1}
As cos-1x is confined between [-1,1] and cosec-1x is not defined between (-1,1) , so only -1 and 1 are left.
So option D is correct .