Limit of (sin(2x))^3/(sin(3x))^3 as x Approaches 0: Solution

In summary: Good luck.Now read the hint I gave in post #2 again. Hopefully you will see it; I'm signing off for tonight. Good luck.In summary, the limit as x approaches 0 of (sin(2x))^3/(sin(3x))^3 can be simplified by using the fact that lim x->0 sinx/x = 1. By multiplying and dividing by certain powers of x, the limit can be rewritten in a form where the limit of sin(x)/x can be used. This leads to the final answer of 8/27, without the use of l'Hopital's rule.
  • #1
Nitrate
75
0

Homework Statement


evaluate the limit as x approaches 0 of (sin(2x))^3/(sin(3x))^3


Homework Equations





The Attempt at a Solution


the answer in the textbook is 8/27
i figured they got that by raising 2 to the 3rd and 3 to the 3rd
but I'm not entirely sure what happens to the sin's

id really appreciate a worked out answer (that doesn't use l'hopital's rule)
 
Physics news on Phys.org
  • #2
Nitrate said:

Homework Statement


evaluate the limit as x approaches 0 of (sin(2x))^3/(sin(3x))^3


Homework Equations





The Attempt at a Solution


the answer in the textbook is 8/27
i figured they got that by raising 2 to the 3rd and 3 to the 3rd
but I'm not entirely sure what happens to the sin's

id really appreciate a worked out answer (that doesn't use l'hopital's rule)

We don't do worked out answers. But here's a hint: Presumably you know something about the limit of sin(x)/x as x → 0. Make use of that by multiplying and dividing by certain powers of x.
 
  • #3
LCKurtz said:
We don't do worked out answers. But here's a hint: Presumably you know something about the limit of sin(x)/x as x → 0. Make use of that by multiplying and dividing by certain powers of x.

well
lim
x->0 sinx/x = 1
the problem is that i don't know how to apply it to this question
 
  • #4
Nitrate said:
well
lim
x->0 sinx/x = 1
the problem is that i don't know how to apply it to this question

What would be the limit of [itex]\frac {\sin(2x)}{2x}[/itex] as x → 0?
 
  • #5
LCKurtz said:
What would be the limit of [itex]\frac {\sin(2x)}{2x}[/itex] as x → 0?
that limit would be 1 as well
but I'm still not sure how it'd help
 
  • #6
Nitrate said:
that limit would be 1 as well
but I'm still not sure how it'd help

Now read the hint I gave in post #2 again. Hopefully you will see it; I'm signing off for tonight.
 

1. What is the limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0?

The limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0 is equal to 8/27.

2. How do you solve the limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0?

To solve this limit, we can use the L'Hopital's rule, which states that the limit of f(x)/g(x) as x approaches a is equal to the limit of f'(x)/g'(x) as x approaches a, where f'(x) and g'(x) are the derivatives of f(x) and g(x) respectively.

3. What is the significance of the limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0?

The limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0 is significant because it is the value that the function approaches as x gets closer and closer to 0. It helps us understand the behavior of the function near the point x = 0.

4. Can you explain why the limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0 is not defined?

The limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0 is not defined because the function is undefined at x = 0. This is because the denominator, (sin(3x))^3, becomes 0 at x = 0, which results in a division by 0 error.

5. How does the value of the limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0 change if we use radians instead of degrees?

The value of the limit of (sin(2x))^3/(sin(3x))^3 as x approaches 0 remains the same regardless of whether we use radians or degrees. This is because the trigonometric functions, sin(2x) and sin(3x), are defined in terms of radians and degrees, and their values are equal at x = 0 in both units.

Similar threads

  • Calculus and Beyond Homework Help
Replies
3
Views
785
  • Calculus and Beyond Homework Help
Replies
23
Views
1K
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
Replies
1
Views
621
  • Calculus and Beyond Homework Help
2
Replies
54
Views
4K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
18
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
2K
  • Calculus and Beyond Homework Help
Replies
11
Views
1K
Back
Top