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📐 Mathematics  ·  Application of Integrals  ·  JEE

If the curve lies entirely below the x-axis over [a,b], the area is:

Answer: The absolute value of the definite integral (which is negative).

  • A Equal to the definite integral, treating it as positive
  • B The absolute value of the definite integral (which is negative)
  • C Zero in this particular case, regardless of the curve's shape
  • D Equal to b minus a, the width of the interval alone

Correct answer: B. The absolute value of the definite integral (which is negative)

Explanation: When f(x) < 0 on [a,b], the definite integral is negative; the actual area is its absolute value.

Area Under a Curve = Definite Integralxyx=ax=bArea = ∫ₐᵇ f(x)dx

The definite integral ∫ₐᵇf(x)dx computes the exact area of the shaded region bounded by the curve, the x-axis, and the vertical lines x=a and x=b - the same idea behind the Riemann sum, but evaluated exactly rather than approximated by rectangles.

Concept context

Using definite integrals to compute the area under a curve, the area between two curves, and the areas enclosed by standard curves like circles, parabolas, and ellipses.

Read the full Application of Integrals notes →