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COMEDK · Maths · 25. Continuity and Differentiability

If the function \(f(x)=\left\{\begin{array}{cl}\frac{1-\cos x}{x^{2}}, & \text { for } x \neq 0 \\ k, & \text { for } x=0\end{array}\right.\) is continuous at \(x=0\), then the value of \(k\) is

  1. A 0
  2. B 1
  3. C \(-1\)
  4. D \(1 / 2\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(1 / 2\)

Step-by-step Solution

Detailed explanation

We have, \[ f(x)=\left\{\begin{array}{cl} \frac{1-\cos x}{x^{2}}, & x \neq 0 \\ k, & x=0 \end{array}\right. \] Since, \(f(x)\) is continuous at \(x=0\), then \(f(0)=\lim _{x \rightarrow 0} f(x) \Rightarrow k=\lim _{x \rightarrow 0} \frac{1-\cos x}{x^{2}}\)…