21
Rationalised 2023-24
 MATHEMATICS
180
Now f ′(x) = 0 gives x = 1, x = – 2, or x = 3 The
points x = 1, – 2, and 3 divide the real line into four
disjoint intervals namely, (– ∞, – 2), (– 2, 1), (1, 3)
and (3, ∞) (Fig 6 22) Consider the interval (– ∞, – 2), i