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JEE Mains · Maths · STD 11- 2. Relation and Function

The sum of all the elements in the range of \(f(x)=\text{Sgn}(\sin x)+\text{Sgn}(\cos x)+\text{Sgn}(\tan x)+\text{Sgn}(\cot x), x\ne\frac{n\pi}{2}, n\in Z\), where \(\operatorname{Sgn}(t)=\left\{\begin{array}{lll}1, & \text { if } & t>0 \\ -1 & \text { if } & t<0\end{array}\right.\), is

  1. A 4
  2. B 2
  3. C -2
  4. D 0
Verified Solution

Answer & Solution

Correct Answer

(B) 2

Step-by-step Solution

Detailed explanation

\(x\in(0,\pi/2)\Rightarrow y=1+1+1+1=4\) \(x\in(\pi/2,\pi)\Rightarrow y=1-1-1-1=-2\) \(x\in(\pi,3\pi/2)\Rightarrow y=-1-1+1+1=0\) \(x\in(3\pi/2,2\pi)\Rightarrow y=-1+1-1-1=-2\) \(\therefore\) Range of y is \(\{-2,0,4\}\) Required sum=\(-2+0+4=2\)
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