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The area (in sq. units) of the region bounded by the curve y=sin⁡x,−2π≤x≤2πy = \sin x, -2\pi \leq x \leq 2\pi and x−axisx - axis is equal to

Solution

✅ Correct Option: 3

The curve y=sin⁡xy = \sin x oscillates above and below the xx-axis. Area is always positive, so the absolute value of the function must be used where it is negative.

For the interval −2π≤x≤2π-2\pi \leq x \leq 2\pi:

sin⁡x≥0\sin x \geq 0 on [−π,0][-\pi, 0] and [0,π][0, \pi]

sin⁡x<0\sin x < 0 on [−2π,−π][-2\pi, -\pi] and [π,2π][\pi, 2\pi]


For 0≤x≤π0 \leq x \leq \pi, where sin⁡x≥0\sin x \geq 0:

Area =∫0πsin⁡x dx= \int_0^\pi \sin x \, dx

=[−cos⁡x]0π= [-\cos x]_0^\pi

=−cos⁡π−(−cos⁡0)= -\cos \pi - (-\cos 0)

=−(−1)+1= -(-1) + 1

=2= 2


For π≤x≤2π\pi \leq x \leq 2\pi, where sin⁡x<0\sin x < 0:

Area =∫π2π∣sin⁡x∣ dx= \int_\pi^{2\pi} |\sin x| \, dx

=∫π2π(−sin⁡x) dx= \int_\pi^{2\pi} (-\sin x) \, dx

=[cos⁡x]π2π= [\cos x]_\pi^{2\pi}

=cos⁡2π−cos⁡π= \cos 2\pi - \cos \pi

=1−(−1)= 1 - (-1)

=2= 2


For −π≤x≤0-\pi \leq x \leq 0, where sin⁡x≥0\sin x \geq 0:

Area =∫−π0sin⁡x dx= \int_{-\pi}^0 \sin x \, dx

=[−cos⁡x]−π0= [-\cos x]_{-\pi}^0

=−cos⁡0−(−cos⁡(−π))= -\cos 0 - (-\cos(-\pi))

=−1+(−1)= -1 + (-1)

=−2= -2

Taking the absolute value: Area =2= 2


For −2π≤x≤−π-2\pi \leq x \leq -\pi, where sin⁡x<0\sin x < 0:

Area =∫−2π−π∣sin⁡x∣ dx= \int_{-2\pi}^{-\pi} |\sin x| \, dx

=∫−2π−π(−sin⁡x) dx= \int_{-2\pi}^{-\pi} (-\sin x) \, dx

=[cos⁡x]−2π−π= [\cos x]_{-2\pi}^{-\pi}

=cos⁡(−π)−cos⁡(−2π)= \cos(-\pi) - \cos(-2\pi)

=−1−1= -1 - 1

=−2= -2

Taking the absolute value: Area =2= 2


Total Area =2+2+2+2= 2 + 2 + 2 + 2

=8= 8

Therefore, the area of the region bounded by the curve and the xx-axis is 88 square units.

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