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Question #40729

Difficulty: 8/10 | 🟢 Free

The Question

Let y=y(x)y = y(x) be the solution to the differential equation dydx+y=∣x−1∣\frac{dy}{dx} + y = |x - 1| satisfying the initial condition y(0)=2y(0) = 2. The minimum value of y(x)y(x) for x∈Rx \in \mathbb{R} is:

Options

  • A.

    ln⁡2\ln 2

  • B.

    2ln⁡2−12 \ln 2 - 1

  • C.

    11

  • D.

    ln⁡2+1\ln 2 + 1

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Bridge

Practice problems that bridge the gap between foundational theory and advanced practical application.

Concepts Behind This Question

Slope Sensitivity|Linear Differential Equation Structure|The Modulus Trap

Why This Question Is Tricky

Common Mistakes

The question tests the 'Modulus Trap' within a Linear Differential Equation.

Students must recognize that the modulus ∣x−1∣|x-1| forces a piece-wise solution.

The critical trap lies in the 'Slope Sensitivity' and continuity: candidates often incorrectly apply the initial condition y(0)=2y(0)=2 directly to the x≥1x \ge 1 branch, bypassing the continuity requirement at x=1x=1.

This leads to an incorrect constant of integration (C=4C=4 instead of 2e2e) and a false minimum of 2ln⁡2−12\ln 2 - 1.

Proper execution requires solving the x<1x < 1 branch first, using the limit at x=1x=1 to find the continuity constant for the x≥1x \ge 1 branch, and then optimizing the resulting curve.

Quick Facts About This Question

Question Information

SubjectMathematics
ChapterStraight Lines - Class 11
ConceptSlope Sensitivity
Difficulty8
Cognitive Load7
Target Solve Time160 sec
AccessFree