Verified Solution • 2025–26 Session moderate

QJEEM24Ma0b52: JEE Main 2024 Mathematics - Class 11 JEEM24Ma0b52 Solution: Let and be defined as and . Then, gof : is :

Let f:R→Rf: \mathbf{R} \rightarrow \mathbf{R} and g:R→Rg: \mathbf{R} \rightarrow \mathbf{R} be defined as

f(x)={log⁡ex,amp;xgt;0e−x,amp;x≤0f(x)=\left\{\begin{array}{ll}\log _{\mathrm{e}} x, & x>0 \\ \mathrm{e}^{-x}, & x \leq 0\end{array}\right. and

g(x)={x,amp;x⩾0ex,amp;xlt;0g(x)=\left\{\begin{array}{ll}x, & x \geqslant 0 \\ \mathrm{e}^x, & x<0\end{array}\right. . Then, gof : R→R\mathbf{R} \rightarrow \mathbf{R} is :

Multiple Choice Options

  • A one-one but not onto
  • B neither one-one nor onto
  • C onto but not one-one
  • D both one-one and onto

Step-by-Step Verified Solution

Given, f(x)={log⁡ex,amp;xgt;0e−x,amp;x≤0f(x)=\left\{\begin{array}{ll}\log _{\mathrm{e}} x, & x>0 \\ \mathrm{e}^{-x}, & x \leq 0\end{array}\right. and

g(x)={x,amp;x⩾0ex,amp;xlt;0g(x)=\left\{\begin{array}{ll}x, & x \geqslant 0 \\ \mathrm{e}^x, & x<0\end{array}\right.

then g∘f(x)g \circ f(x) =g(f(x))=g(f(x))

amp;g(f(x))={f(x),f(x)≥0ef(x),f(x)lt;0amp;g(f(x))={e−x,(−∞,0]eln⁡x,(0,1)ln⁡x,[1,∞)\begin{aligned} & \mathrm{g}(\mathrm{f}(\mathrm{x}))=\left\{\begin{array}{l}f(x), f(x) \geq 0 \\ e^{f(x)}, f(x)<0\end{array}\right. \\\\ & \mathrm{g}(\mathrm{f}(\mathrm{x}))=\left\{\begin{array}{l}e^{-x},(-\infty, 0] \\ e^{\ln x},(0,1) \\ \ln x,[1, \infty)\end{array}\right.\end{aligned}

g(f(x))={e−x,(−∞,0]x,(0,1)ln⁡x,[1,∞)g(f(x))=\left\{\begin{array}{c}e^{-x},(-\infty, 0] \\ x,(0,1) \\ \ln x,[1, \infty)\end{array}\right.

JEE Main 2024 (Online) 1st February Morning Shift Mathematics - Functions Question 29 English Explanation

From the graph of g(f(x))g(f(x)) , we can say

g(f(x))⇒\mathrm{g}(\mathrm{f}(\mathrm{x})) \Rightarrow Many one into

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