A rational function f(x) and its first derivative are given below:
f(x) = 6/x²-1, f'(x) = -12x / (x-1)²(x+1)²
Find the intervals over which the function f(x) is decreasing.
a. (-1,1)
b. (-[infinity],0)
c. (-[infinity],-1) and (-1,0)
d. (0,1) and (1,[infinity])
e. (-[infinity],-1) and (1,[infinity])
f. None of the above.