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📐 Mathematics  ·  Continuity and Differentiability  ·  JEE

If f and g are continuous at x = a, then f/g is continuous at a provided:

Answer: g(a) is not equal to 0.

  • A f(a) = 0
  • B g(a) = 0
  • C g(a) is not equal to 0
  • D f(a) is not equal to 0

Correct answer: C. g(a) is not equal to 0

Explanation: The quotient of two continuous functions is continuous wherever the denominator is nonzero.

f(x) = |x|: Continuous but NOT Differentiable at 0x=0 (sharp "kink")LHD = -1RHD = +1LHD ≠ RHD at the kink → not differentiable, even though the curve has no gap (continuous)

f(x)=|x| is perfectly continuous at x=0 (no break, no jump), but the curve has a sharp corner there: approaching from the left gives slope -1 and from the right gives slope +1 - since these one-sided derivatives disagree, the function is not differentiable at that point.

Concept context

When a function has no breaks (continuity) and when it has a well-defined slope (differentiability), plus rules for differentiating implicit, inverse trig, exponential, log, and parametric functions.

Read the full Continuity and Differentiability notes →