Let f be a real valued function, defined on  R−−1,  1 and given by          fx=3logex−1x+1−2x−1.  Then in which of the following intervals, function fx  is increasing?

Given fx=3logex−1x+1−2x−1.Differentiate both sides with respect to xf'x=3x−1x+1×x+1−x+1x+12+2x+12=2x+13x+1+1x−1=4x−12x+12x−1 The function fx is increasing when 2x-1x+1>0 and x not equal to 1 x∈−∞,−1∪12,∞−1