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PEAMCQModerate Needs review

2023 PEA Q20

ff differentiable, ff' strictly increasing. f(1/2)=1/2,  f(1)=1f(1/2)=1/2,\;f(1)=1. Compare f(1/2),  1,  f(1)f'(1/2),\;1,\;f'(1).

The available source text does not include a full option block for this item, so the question is marked needsReview.
Reveal answer and solution

Answer

C

Solution

  1. 1

    By the Mean Value Theorem on [1/2,1][1/2,1], there exists c(1/2,1)c\in(1/2,1) with

  2. 2
    f(c)=f(1)f(1/2)11/2=1/21/2=1. f'(c)=\frac{f(1)-f(1/2)}{1-1/2}=\frac{1/2}{1/2}=1.
  3. 3

    Since ff' is strictly increasing, f(1/2)<f(c)=1<f(1)f'(1/2)<f'(c)=1<f'(1).

Answer structure / marking notes

Needs review: source TeX does not provide a full four-option MCQ block.

Content note

Imported from public/resources/isi/msqe/solutions/pea/2023/ISI_MSQE_PEA_2023_Solutions.tex. Question wording is retained from the available local TeX source; incomplete option blocks or ambiguous source status are flagged for review.