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MCQ practice · SSC Higher Mathematics Board questions · Chapter 1: Set and Function

Jashore Board 2024

If S = {(x, y) : x² + y² = 25}, which of the following is correct?

  1. i. The graph of S is a circle
  2. ii. Under −5 ≤ y ≤ 0, S is a function
  3. iii. Under 0 ≤ y ≤ 5, S is a function

Think it through first, then pick an option.

  1. a i and ii
  2. b i and iii
  3. c ii and iii
  4. d i, ii and iii
Answer and explanation

Correct answer: d i, ii and iii

The circle is not a function, but its upper or lower half alone is.

Why the other options are wrong

  • a i and ii: iii is true too: 0 ≤ y ≤ 5 gives the upper semicircle, which is a function.
  • b i and iii: ii is true too: −5 ≤ y ≤ 0 gives the lower semicircle, which is a function.
  • c ii and iii: i is true too: it is the circle with centre (0, 0) and radius 5.