Is my approach to finding the limit of trig functions correct?

  • Thread starter jkristia
  • Start date
  • Tags
    Limit Trig
In summary, the correct approach for solving the limit of (sin 2x) / (sin 3x) as x approaches 0 is to first manipulate the equation to the form (sin x) / x or x / (sin x) and then use the given steps to get the final answer of 2/3. The use of L'Hospital's principle is another method, but this approach is considered more elegant.
  • #1
jkristia
54
0
I'm still trying to figure out how to do limits of trig functions and I would like to know if this is the correct approach. I know the answer is correct, but not sure if that is just a coincidence.

Homework Statement



lim (x -> 0) of (sin 2x) / (sin3x).

Homework Equations


The Attempt at a Solution



First I try to get the equation into the form (sin x) / x or x / (sin x)
so I multiply by

(x/x)(3/3)(2/2)

this gives me

(1/3)(3x/sin3x)(2/1)(sin2x/2x)

so I get
(1/3)(1)(2/1)(1) = 2/3

Is that the correct approach?
 
Physics news on Phys.org
  • #2
Yes, it is :smile:

Edit : Another way to solve this would be the use of L'Hospital principle, but this method is more elegant, in my opinion.
 
  • #3
Thank you very much for the quick reply.

I'm trying to do calculus as a selfstudy, and the L'Hospital is not mentioned until another 320 pages.
 

Related to Is my approach to finding the limit of trig functions correct?

1. What is a trig limit?

A trigonometric limit is a mathematical concept in calculus that refers to the value that a trigonometric function approaches as its input (usually an angle) approaches a specific value, such as infinity or zero.

2. How do you solve a trig limit?

To solve a trigonometric limit, you need to use algebraic manipulation and trigonometric identities to simplify the expression. Then, you can use techniques such as substitution, factoring, or L'Hopital's Rule to evaluate the limit.

3. What are some common trigonometric limits?

Some commonly encountered trigonometric limits include the limits of sine, cosine, and tangent functions as their input approaches 0 or infinity. For example, the limit of sin(x)/x as x approaches 0 is equal to 1, while the limit of tan(x)/x as x approaches 0 is equal to 1.

4. Can trigonometric limits be undefined?

Yes, it is possible for a trigonometric limit to be undefined if the function has a vertical asymptote or if the limit does not exist due to oscillation or divergence. In these cases, the limit is said to be "does not exist" or "DNE".

5. How can I check if my trig limit calculation is correct?

To check if your trigonometric limit calculation is correct, you can use a graphing calculator or an online limit calculator to confirm the value. You can also plug in different values for the limit's input to see if the limit follows the expected pattern or behavior.

Similar threads

  • Calculus and Beyond Homework Help
Replies
2
Views
199
  • Calculus and Beyond Homework Help
Replies
6
Views
742
  • Calculus and Beyond Homework Help
Replies
2
Views
893
  • Calculus and Beyond Homework Help
Replies
3
Views
773
  • Calculus and Beyond Homework Help
Replies
8
Views
735
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
786
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
384
  • Calculus and Beyond Homework Help
Replies
13
Views
2K
Back
Top