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Match List-I with List-II

Where R\mathbb{R} is set of real numbers

List-IList-II
(A) sin⁡x\sin x is continuous on:(I) R−{0}\mathbb{R} - \{0\}
(B) tan⁡x \tan x is continuous on:(II) R\mathbb{R}
(C) cot⁡x\cot x is continuous on:(III) R−{nπ:n∈Z}\mathbb{R} - \{n\pi: n \in \mathbb{Z}\}
(D) x−n,n∈Nx^{-n}, n \in \mathbb{N} is continuous on:(IV) R−{(2n+1)π2:n∈Z}\mathbb{R} - \left\{(2n + 1)\frac{\pi}{2}: n \in \mathbb{Z}\right\}

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 2

A function is continuous on a set if there's no break, jump, or hole in its graph at every point in that set. A function is not continuous where it's undefined.


sin⁡x\sin x is defined for all real numbers. The graph is a smooth wave with no breaks anywhere.

sin⁡x\sin x is continuous on R\mathbb{R}

(A) matches with (II)


tan⁡x=sin⁡xcos⁡x\tan x = \frac{\sin x}{\cos x}

tan⁡x\tan x is undefined when cos⁡x=0\cos x = 0

cos⁡x=0\cos x = 0 at x=π2,3π2,5π2,−π2,−3π2,...x = \frac{\pi}{2}, \frac{3\pi}{2}, \frac{5\pi}{2}, -\frac{\pi}{2}, -\frac{3\pi}{2}, ...

General form: x=(2n+1)π2x = (2n + 1)\frac{\pi}{2} where n∈Zn \in \mathbb{Z}

tan⁡x\tan x is continuous on R−{(2n+1)π2:n∈Z}\mathbb{R} - \left\{(2n + 1)\frac{\pi}{2}: n \in \mathbb{Z}\right\}

(B) matches with (IV)


cot⁡x=cos⁡xsin⁡x\cot x = \frac{\cos x}{\sin x}

cot⁡x\cot x is undefined when sin⁡x=0\sin x = 0

sin⁡x=0\sin x = 0 at x=0,π,2π,3π,−π,−2π,...x = 0, \pi, 2\pi, 3\pi, -\pi, -2\pi, ...

General form: x=nπx = n\pi where n∈Zn \in \mathbb{Z}

cot⁡x\cot x is continuous on R−{nπ:n∈Z}\mathbb{R} - \{n\pi: n \in \mathbb{Z}\}

(C) matches with (III)


x−n=1xnx^{-n} = \frac{1}{x^n} where n∈Nn \in \mathbb{N}

This is undefined when x=0x = 0

x−nx^{-n} is continuous on R−{0}\mathbb{R} - \{0\}

(D) matches with (I)


Final matching:

(A) sin⁡x\sin x → (II) R\mathbb{R}

(B) tan⁡x\tan x → (IV) R−{(2n+1)π2:n∈Z}\mathbb{R} - \left\{(2n + 1)\frac{\pi}{2}: n \in \mathbb{Z}\right\}

(C) cot⁡x\cot x → (III) R−{nπ:n∈Z}\mathbb{R} - \{n\pi: n \in \mathbb{Z}\}

(D) x−nx^{-n} → (I) R−{0}\mathbb{R} - \{0\}

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