For trigonometric functions like \( \cot(x) \), look for values where the denominator of the function becomes zero. For \( \cot(x) = \frac{\cos(x)}{\sin(x)} \), the function is undefined whenever \( \sin(x) = 0 \), which happens at multiples of \( \pi \). These are the points of discontinuity.
The correct answer is: (B) \( \left\{ x = n\pi ;\ n \in \mathbb{Z} \right\} \).
The function \( f(x) = \cot(x) \) is discontinuous at points where the denominator of the cotangent function is zero. The cotangent function is defined as:
\( \cot(x) = \frac{\cos(x)}{\sin(x)} \)
The function \( \cot(x) \) is undefined when \( \sin(x) = 0 \), which occurs at multiples of \( \pi \), i.e., \( x = n\pi \), where \( n \in \mathbb{Z} \) (the set of all integers). Therefore, \( f(x) = \cot(x) \) is discontinuous at \( x = n\pi \), for \( n \in \mathbb{Z} \). Thus, the correct answer is (B) \( \left\{ x = n\pi ;\ n \in \mathbb{Z} \right\} \).Prove that the function \( f(x) = |x| \) is continuous at \( x = 0 \) but not differentiable.
\[ f(x) = \begin{cases} x^2 + 2, & \text{if } x \neq 0 \\ 1, & \text{if } x = 0 \end{cases} \]
is not continuous at \( x = 0 \).Is the function \( f(x) \) defined by
\[ f(x) = \begin{cases} x + 5, & \text{if } x \leq 1 \\ x - 5, & \text{if } x > 1 \end{cases} \]
continuous at \( x = 1 \)?