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The area (in sq. units) of the region bounded by y=−1,y=2,x=y3y = -1, y = 2, x = y^3 and x=0x = 0 is equal to

Solution

✅ Correct Option: 3

The area is enclosed by:

  • y=−1y = -1 (bottom horizontal line)
  • y=2y = 2 (top horizontal line)
  • x=y3x = y^3 (curved line)
  • x=0x = 0 (the y-axis)

Since the boundaries are given as functions of yy, integrate with respect to yy.


The curve x=y3x = y^3 position relative to the y-axis:

At y=−1y = -1: x=(−1)3=−1x = (-1)^3 = -1 (left of y-axis)

At y=0y = 0: x=03=0x = 0^3 = 0 (on the y-axis)

At y=2y = 2: x=23=8x = 2^3 = 8 (right of y-axis)

The curve crosses from left to right at y=0y = 0, so the region must be split at this point.


For y=−1y = -1 to y=0y = 0:

Right boundary: x=0x = 0

Left boundary: x=y3x = y^3 (negative values)

Width: 0−y3=−y30 - y^3 = -y^3

For y=0y = 0 to y=2y = 2:

Right boundary: x=y3x = y^3 (positive values)

Left boundary: x=0x = 0

Width: y3−0=y3y^3 - 0 = y^3


Total Area=∫−10(−y3) dy+∫02y3 dy\text{Total Area} = \int_{-1}^{0} (-y^3) \, dy + \int_{0}^{2} y^3 \, dy


∫−10(−y3) dy=[−y44]−10\int_{-1}^{0} (-y^3) \, dy = \left[-\frac{y^4}{4}\right]_{-1}^{0}

=−(0)44−(−(−1)44)= -\frac{(0)^4}{4} - \left(-\frac{(-1)^4}{4}\right)

=0+14= 0 + \frac{1}{4}

=14= \frac{1}{4}


∫02y3 dy=[y44]02\int_{0}^{2} y^3 \, dy = \left[\frac{y^4}{4}\right]_{0}^{2}

=(2)44−(0)44= \frac{(2)^4}{4} - \frac{(0)^4}{4}

=164= \frac{16}{4}

=4= 4


Total Area=14+4\text{Total Area} = \frac{1}{4} + 4

=14+164= \frac{1}{4} + \frac{16}{4}

=174= \frac{17}{4}

Therefore, the area of the region is 174\frac{17}{4} square units.

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