Chapter 1: Problem 41
In Problems \(41-48,\) determine whether the function is continuous at the given point c. If the function is not continuous, determine whether the discontinuity is removable or nonremovable. $$ f(x)=\sin x ; c=0 $$
Short Answer
Expert verified
The function \( f(x) = \sin x \) is continuous at \( c = 0 \) with no discontinuities.
Step by step solution
01
Identify the function and point
The problem asks us to determine the continuity of the function \( f(x) = \sin x \) at the point \( c = 0 \).
02
Understand Continuity
A function is continuous at a point \( c \) if the following conditions are met: 1) \( f(c) \) is defined, 2) The limit \( \lim_{x \to c} f(x) \) exists, and 3) \( \lim_{x \to c} f(x) = f(c) \).
03
Check if \( f(x) \) is defined at \( c \)
The function \( f(x) = \sin x \) is defined for all real numbers, including \( x = 0 \). Therefore, \( f(0) = \sin 0 = 0 \).
04
Evaluate the limit of \( f(x) \) as \( x \to 0 \)
Find \( \lim_{x \to 0} \sin x \). As \( x \) approaches 0, \( \sin x \) approaches \( \sin 0 = 0 \). Thus, \( \lim_{x \to 0} \sin x = 0 \).
05
Compare limit with function value at \( c \)
We found that \( f(0) = 0 \) and \( \lim_{x \to 0} \sin x = 0 \). Since the limit equals the function value, \( \sin x \) is continuous at \( x = 0 \).
06
Determine if there is any discontinuity
Since the function is continuous at \( x = 0 \), there are no discontinuities (removable or non-removable) at this point.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Sine Function
The sine function, denoted as \( \sin x \), is a fundamental trigonometric function that measures the y-coordinate of a point on the unit circle as the angle \( x \) varies. It's periodic with a period of \( 2\pi \), meaning it repeats its values every \( 2\pi \) radians. The range of the sine function is from -1 to 1, making it bounded. Additionally, it is defined for every real number \( x \), ensuring its widespread applicability in many mathematics problems. Hence, at any angle including \( x = 0 \), \( \sin x \) is well-defined, and as we will see, it plays a key role in determining continuity at certain points.
Limits
Limits are a core concept in calculus and analyze the behavior of functions as they approach a certain point. For a function \( f(x) \), the limit \( \lim_{x \to c} f(x) \) tells us what value \( f(x) \) approaches as \( x \) gets infinitely close to \( c \). In the case of the sine function at \( x = 0 \), we evaluate how \( \sin x \) behaves as it nears 0. Calculating \( \lim_{x \to 0} \sin x \), we find it equals \( \sin 0 = 0 \). Thus, the limit aligns perfectly with the actual function value at 0, which is a crucial factor in assessing the function's continuity.
Continuous Function
A continuous function is one that does not have any jumps, breaks, or holes at a given point. Formally, a function \( f(x) \) is continuous at a point \( c \) if three conditions are met:
- \( f(c) \) is defined.
- The limit \( \lim_{x \to c} f(x) \) exists.
- The limit equals the function value at \( c \), i.e., \( \lim_{x \to c} f(x) = f(c) \).
Removable Discontinuity
A removable discontinuity occurs in a function when there is a hole at a certain point that can often be "fixed" by re-defining the function value at that point. However, in the case of \( \sin x \) at \( x = 0 \), there is no hole or gap. The function is smooth and continuous, meaning there are no removable discontinuities. If there were a removable discontinuity, we would see a break or gap in the graph that could be corrected, but for \( \sin x \), this is not the case.
Nonremovable Discontinuity
Nonremovable discontinuities are more stubborn and cannot be eliminated by simple redefinition. They occur when the limits from the left-hand and right-hand sides of a function do not match or when a function goes to infinity at a point. In our sine function at \( x = 0 \), no such discrepancies exist. The left-hand and right-hand limits as \( x \to 0 \) match perfectly, and \( \sin x \) does not go to infinity. Hence, the sine function exhibits no nonremovable discontinuities at \( x = 0 \), maintaining its continuity without any breaks or infinite behaviors.