Q41 / 90 · NTA Abhyas (JEE Main) 2020 · Mathematics · Area Under Curves

The area (in sq. units) bounded between the curves y=excos⁡x and y=exsin⁡x from x=π4 to x=π2 is

  • A
    eπ2
  • Correct answer
    B
    eπ42
  • C
    eλ2
  • D
    eλ2

Solution

As sin⁡x>cos⁡x, ∀x∈π4,π2
⇒exsin⁡x>excos⁡x
Thus the required area is
A=∫π4π2exsin⁡x-excos⁡xdx
=-∫π4π2excos⁡x+-sin⁡xdx
=-excos⁡xπ4π2
=− 0− e π 4 ⋅ 1 2
=eπ42
As∫ e x f x + f ′ x dx= e x ⋅f x +C

Hence, the correct answer is option: 'B'.

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