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📐 Mathematics  ·  Integrals  ·  JEE

Integral of (x+1)/((x+2)(x+3)) dx using partial fractions:

Answer: -ln|x+2| + 2ln|x+3| + C.

  • A -ln|x+2| + 2ln|x+3| + C
  • B ln|x+2| + ln|x+3| + C
  • C (x+1)/(x+2)(x+3) + C
  • D 2ln|x+3| - ln|x+2| + C

Correct answer: A. -ln|x+2| + 2ln|x+3| + C

Explanation: Partial fractions: (x+1)/[(x+2)(x+3)] = A/(x+2)+B/(x+3). Setting x=−2: A=−1; x=−3: B=2. Integral = −∫dx/(x+2)+2∫dx/(x+3) = −ln|x+2|+2ln|x+3|+C.

xyabArea = integral of f(x) dxRectangles approximate the area (Riemann sum)

The exact area under the curve from a to b (shaded) is approximated by a few rectangles, the Riemann sum idea behind the definite integral.

Concept context

Indefinite and definite integrals, areas under curves

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