Trigonometric Limit: Solving (sin 2x)/(sin 5x) as x Approaches 0

Xarkoth
Messages
2
Reaction score
0

Homework Statement


lim (sin 2x)/(sin 5x)
x->0

Could someone please help me get started, I simply can't figure this one out.

Homework Equations


The Attempt at a Solution

 
Last edited:
Physics news on Phys.org
Do you know this limit?
\lim_{x \to 0} \frac{sin x}{x} = 1

To evaluate your limit, you need sin(2x)/2x and 5x/sin(5x). Multiply your expression by 1 in the appropriate form to get these two quotients.
 
I figured it out, thanks man.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top