Asksia AI LOGO

Sia

Question
Math
Posted 5 months ago

We want to find limx0xsin(x)\lim _{x \rightarrow 0} \frac{x}{\sin (x)}. Direct substitution and other algebraic methods don't seem to work.

Looking at the graph of f(x)=xsin(x)f(x)=\frac{x}{\sin (x)}, we can estimate that the limit is equal to 1 .

To prove that limx0xsin(x)=1\lim _{x \rightarrow 0} \frac{x}{\sin (x)}=1, we can use the squeeze theorem.
Pablo suggested that we use the functions g(x)=x2+0.5g(x)=-x^{2}+0.5 and h(x)=x2+1.5h(x)=x^{2}+1.5 in order to apply the squeeze theorem.

Does Pablo's suggestion seem to be correct?
Choose 1 answer:
(A) Yes, Pablo's suggestion seems to be correct.
(B) No, Pablo's suggestion is incorrect because it's not true that one function is always below ff and one function is always above it for xx-values near 0 .
(C) No, Pablo's suggestion is incorrect because it's not true that the limits of gg and hh are both equal to 1 .
Sign in to unlock the answer
Answer from Sia
Posted 5 months ago
Solution by Steps
step 2
The squeeze theorem states that if g(x)f(x)h(x)g(x) \leq f(x) \leq h(x) for all xx in some interval around 00 (except possibly at 00 itself), and limx0g(x)=limx0h(x)=L\lim_{x \to 0} g(x) = \lim_{x \to 0} h(x) = L, then limx0f(x)=L\lim_{x \to 0} f(x) = L
step 3
First, we check the limits of g(x)g(x) and h(x)h(x) as xx approaches 00
step 4
limx0g(x)=limx0(x2+0.5)=0.5\lim_{x \to 0} g(x) = \lim_{x \to 0} (-x^2 + 0.5) = 0.5
step 5
limx0h(x)=limx0(x2+1.5)=1.5\lim_{x \to 0} h(x) = \lim_{x \to 0} (x^2 + 1.5) = 1.5
step 6
Since the limits of g(x)g(x) and h(x)h(x) are not equal to 11, Pablo's suggestion is incorrect
C
Key Concept
Squeeze Theorem
Explanation
The squeeze theorem requires that the limits of the bounding functions be equal to the limit of the function in question. Since the limits of g(x)g(x) and h(x)h(x) are not equal to 11, they cannot be used to apply the squeeze theorem in this case.

Not the question you are looking for? Ask here!

Enter question by text

Enter question by image

Upgrade to Asksia Pro

Join a AskSia's Pro Plan, and get 24/7 AI tutoring for your reviews, assignments, quizzes and exam preps.

Unlimited chat query usages
Strong algorithms that better know you
Early access to new release features
Study Other Question