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The area (in sq.units) of the region enclosed by the curve y=cos⁡xy = \cos x, −π2≤x≤π2\frac{-\pi}{2} \leq x \leq \frac{\pi}{2} and the x - axis is:

Solution

✅ Correct Option: 2

The region is enclosed by the curve y=cos⁡xy = \cos x, the x-axis, and the vertical lines x=−π2x = \frac{-\pi}{2} and x=π2x = \frac{\pi}{2}.

For this interval:

  • At x=−π2x = \frac{-\pi}{2}: cos⁡(−π2)=0\cos(\frac{-\pi}{2}) = 0
  • At x=0x = 0: cos⁡(0)=1\cos(0) = 1
  • At x=π2x = \frac{\pi}{2}: cos⁡(π2)=0\cos(\frac{\pi}{2}) = 0

The curve y=cos⁡xy = \cos x is always positive (above the x-axis) in the interval [−π2,π2][\frac{-\pi}{2}, \frac{\pi}{2}].


The area under the curve is given by:

Area =∫−π/2π/2cos⁡x dx= \int_{-\pi/2}^{\pi/2} \cos x \, dx


The antiderivative of cos⁡x\cos x is sin⁡x\sin x:

∫cos⁡x dx=sin⁡x+C\int \cos x \, dx = \sin x + C


Evaluating the definite integral:

Area =[sin⁡x]−π/2π/2= [\sin x]_{-\pi/2}^{\pi/2}

Area =sin⁡(π2)−sin⁡(−π2)= \sin(\frac{\pi}{2}) - \sin(\frac{-\pi}{2})

Area =1−(−1)= 1 - (-1)

Area =1+1= 1 + 1

Area =2= 2

Therefore, the area of the region is 22 square units.

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