Calculating the Limit: $\displaystyle \frac{\sqrt{x}}{\sqrt{sinx}}$

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In summary, to calculate the limit of $\displaystyle \frac{\sqrt{x}}{\sqrt{sinx}}$ as x approaches 0, L'Hopital's rule can be used. It can also be calculated using the squeeze theorem. The limit is equal to 1. If x approaches infinity, the limit is equal to infinity. However, this limit is not defined for all values of x, as it is undefined at x = 0 and for any values where sinx is negative. This limit cannot be used to find the slope of a curve at a specific point, as it only describes the behavior of the function as x approaches a certain value.
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whatlifeforme
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Homework Statement


Find the limit.

Homework Equations


lim(x->0+) [itex]\displaystyle \frac{\sqrt{x}}{\sqrt{sinx}}[/itex]

The Attempt at a Solution


How should I approach this? I tried taking l'hopitals rule a few times but did not get anywhere.
 
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  • #2
Are you familiar with the definition of a continuous function?
 
  • #3
hi whatlifeforme! :smile:
whatlifeforme said:
I tried taking l'hopitals rule a few times but did not get anywhere.

try squaring it first :wink:
 

1. How do you calculate the limit of $\displaystyle \frac{\sqrt{x}}{\sqrt{sinx}}$ as x approaches 0?

To calculate this limit, we can use the L'Hopital's rule, which states that the limit of a quotient of two functions is equal to the limit of the derivative of the numerator divided by the derivative of the denominator. In this case, the derivative of $\sqrt{x}$ is $\frac{1}{2\sqrt{x}}$ and the derivative of $\sqrt{sinx}$ is $\frac{cosx}{2\sqrt{sinx}}$. So the limit can be rewritten as $\displaystyle \lim_{x\to0} \frac{\frac{1}{2\sqrt{x}}}{\frac{cosx}{2\sqrt{sinx}}}$. After simplifying, we get the limit as 1.

2. Can this limit be calculated without using L'Hopital's rule?

Yes, this limit can also be calculated using the squeeze theorem. We can bound the function $\displaystyle \frac{\sqrt{x}}{\sqrt{sinx}}$ between two other functions whose limits are easy to find as x approaches 0. For example, we can use the functions $\frac{1}{\sqrt{x}}$ and $\frac{1}{\sqrt{sinx}}$ as upper and lower bounds, respectively. By taking the limit of these two functions, we can conclude that the limit of $\displaystyle \frac{\sqrt{x}}{\sqrt{sinx}}$ is also 1.

3. What happens to the limit if x approaches infinity?

If x approaches infinity, the limit of $\displaystyle \frac{\sqrt{x}}{\sqrt{sinx}}$ is equal to infinity. This can be seen by using the fact that the square root function and the sine function are both unbounded as x approaches infinity, so their quotient will also be unbounded.

4. Is this limit defined for all values of x?

No, this limit is not defined for all values of x. It is not defined at x = 0, as the denominator becomes 0 and the function becomes undefined. It is also not defined for any values of x where sinx is negative, as the square root of a negative number is not a real number.

5. Can this limit be used to find the slope of a curve at a specific point?

No, this limit cannot be used to find the slope of a curve at a specific point. The limit only tells us the behavior of the function as x approaches a certain value, but it does not give us any information about the function at that specific point. To find the slope of a curve at a specific point, we need to use the derivative of the function at that point.

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