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MathsMediumMCQ2021 · 17 Mar Shift 2

Q73.Consider the function f : R →R defined by f(x) = { (2 −sin(0, x1 )) x , xx =≠00 (1) monotonic on (−∞, 0) ∪(0, ∞) (2) not monotonic on (−∞, 0) and (0, ∞) (3) monotonic on (0, ∞) only (4) monotonic on (−∞, 0) only

What This Question Tests

This question asks about the monotonicity of a piecewise function defined using sin(1/x). It requires calculating the derivative and analyzing its sign in different intervals, especially around the point of discontinuity, testing conceptual understanding rather than just computation.

Concepts Tested

Monotonicity (increasing/decreasing functions)Derivative test for monotonicityLimit definitions for function behavior near discontinuities

Formulas Used

f'(x) > 0 for strictly increasing

f'(x) < 0 for strictly decreasing

Derivatives of trigonometric functions

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