The problem asks us to evaluate the limit:
x→0−lim∣x∣x([x]+∣x∣)sin[x]
First, consider the Greatest Integer Function,
[x]. By definition, it returns the largest integer less than or equal to
x. For any
x in the interval
(−1,0), the integer immediately to the left is
−1. Thus, we have:
[x]=−1
Next, consider the Modulus Function,
∣x∣. We know that
∣x∣=−x for all
x<0. Since our interval is strictly negative, we substitute:
∣x∣=−x
Now, we substitute these defined values back into our original expression:
x→0−lim−xx(−1+(−x))sin(−1)
We observe a common factor of
x in both the numerator and the denominator. Because the limit process implies
x approaches
0 but never equals
0, we are mathematically justified in canceling
x:
x→0−lim−1(−1−x)sin(−1)
Recall the odd function property of trigonometry, where
sin(−θ)=−sin(θ). Therefore,
sin(−1)=−sin(1). Substituting this into our expression yields:
x→0−lim−1(−1−x)(−sin1)
Dividing by
−1 effectively flips the signs of the numerator, transforming
(−1−x) into
(1+x). The expression simplifies to:
(1+x)(−sin1)
Since the expression is now continuous at
x=0, we perform the final substitution:
(1+0)(−sin1)=−sin1