If f\left( x \right) = \frac{4x}{4x + 2}, then f\left( x \right) + f\left( 1 - x \right) is equal to-
Step-by-Step Solution
Key Concept: Break domain at x=2 where [x] changes.
<div class="solution"><p><strong>Key Idea:</strong> Break domain at x=2 where [x] changes.</p><p><strong>Step 1:</strong> <span class="math-inline">\(x\in(1,2)\)</span>: <span class="math-inline">\(f(x)=x-1\)</span>, range (0,1)</p><p><strong>Step 2:</strong> <span class="math-inline">\(x\in[2,3)\)</span>: <span class="math-inline">\(f(x)=1+(x-2)^2\)</span>, range [1,2)</p><p><strong>Step 3:</strong> Inverting: <span class="math-block">\[f^{-1}(x) = \begin{cases}x+1, & x\in(0,1)\\ 2+\sqrt{x-1}, & x\in[1,2)\end{cases}\]</span></p><div class="trap-box"><strong>Trap:</strong> Do not use <span class="math-inline">\(2-\sqrt{x-1}\)</span> in second branch — that violates <span class="math-inline">\(x\ge 2\)</span>.</div><div class="key-concept"><strong>Key Concept:</strong> Piecewise GIF/fractional-part inverse via interval splitting</div></div>
Correct Answer: A