Continuity of arctan x / x at 0.

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In summary, continuity is a mathematical concept that describes the smoothness and unbrokenness of a function. The formula for arctan x / x is arctan(x)/x, where arctan(x) is the inverse tangent of x. The continuity of arctan x / x at 0 is important because it allows us to evaluate the function at that point and use it in other calculations. The continuity of arctan x / x at 0 can be determined by evaluating the limit of the function as x approaches 0. Additionally, the continuity of arctan x / x at 0 can be proven using the epsilon-delta definition of continuity, which involves showing that for any given positive number (epsilon),
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mariush
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Homework Statement


f:R->R is defined as f(x) when x[itex]\neq 0[/itex], and 1 when x=0.

Find f'(0).




Homework Equations





The Attempt at a Solution


Since I can prove that f is continuous at x=0, does that allow me to take the the limit of f'(x) as x-> 0, which is 0? It is quite easy to see that the correct answer must be f'(0)=0, but do i break any rules if I first differentiate f(x) and then look at the limit as x-> 0?

Thanks!
 
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  • #2
Just use lim(h→0) (f(x+h)-f(x))/h
 

Related to Continuity of arctan x / x at 0.

1. What is the definition of continuity?

Continuity is a mathematical concept that describes the smoothness and unbrokenness of a function. A function is said to be continuous if there are no sudden jumps or breaks in its graph.

2. What is the formula for arctan x / x?

The formula for arctan x / x is arctan(x)/x, where arctan(x) is the inverse tangent of x.

3. Why is continuity of arctan x / x at 0 important?

The continuity of arctan x / x at 0 is important because it allows us to evaluate the function at that point and use it in other calculations. It also helps us understand the behavior of the function near 0.

4. How is continuity of arctan x / x at 0 determined?

The continuity of arctan x / x at 0 can be determined by evaluating the limit of the function as x approaches 0. If the limit exists and is equal to the function value at 0, then the function is continuous at 0.

5. Can the continuity of arctan x / x at 0 be proven using the epsilon-delta definition of continuity?

Yes, the continuity of arctan x / x at 0 can be proven using the epsilon-delta definition of continuity. This involves showing that for any given positive number (epsilon), there exists a positive number (delta) such that if the distance between x and 0 is less than delta, then the distance between f(x) and f(0) is less than epsilon.

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