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Mathematics20271 markAssertion-reasonIntegrals

Study the Assertion and Reason and choose the correct option.

∫₋₁¹ (x³)/(cos x) dx = 0

Assertion: $\int_{-1}^1 \frac{x^3}{\cos x} dx = 0$

Reason: If $f(x)$ is a continuous function defined on $[0, a]$, then $\int_0^a f(x) dx = \int_0^a f(a-x) dx$

  • aBoth Assertion and Reason are true, and Reason is the correct explanation of Assertion.
  • bBoth Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
  • cAssertion is true and Reason is false.
  • dAssertion is false and Reason is true.

Answer

Answer

Official answer key

Correct option: b

Answer: (b) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion. $f(x) = \frac{x^3}{\cos x}$ is odd, because $f(-x) = -f(x)$, so $\int_{-1}^{1} \frac{x^3}{\cos x}dx = 0$. The Reason is a valid property of definite integrals, but it is not what makes this integral zero (the odd-function property does).