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CA Foundation · Quantitative Aptitude · Sets, Relations and Functions, Limits and Continuity

The function f(x) = px + 3 for x ≤ 2, and f(x) = x² + q for x > 2, is continuous everywhere. If p = 4, what is the value of q?

q equals 7. At x = 2 the left piece gives 4(2) + 3 = 11, while the right piece tends to 4 + q. For continuity the two must be equal, so 4 + q = 11 and q = 7.

  1. A3
  2. B7Correct
  3. C−1
  4. D11

Explanation

Left-hand value at 2 is 4(2) + 3 = 11. Right-hand limit is 4 + q. Continuity needs 4 + q = 11, so q = 7. Choosing 3 or 11 comes from ignoring the x² term, and −1 from a sign error.

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