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The area bounded by the curve y=4+3x−x2y = 4 + 3x - x^2 and xx-axis is equal to

Solution

✅ Correct Option: 1

The area bounded by the curve y=4+3x−x2y = 4 + 3x - x^2 and the x-axis is found by determining where the curve intersects the x-axis and integrating between those points.


The curve touches the x-axis when y=0y = 0:

4+3x−x2=04 + 3x - x^2 = 0

x2−3x−4=0x^2 - 3x - 4 = 0

(x−4)(x+1)=0(x - 4)(x + 1) = 0

Therefore x=4x = 4 or x=−1x = -1


The curve is above the x-axis between x=−1x = -1 and x=4x = 4, so the area is:

Area=∫−14(4+3x−x2) dx\text{Area} = \int_{-1}^{4} (4 + 3x - x^2) \, dx

=[4x+3x22−x33]−14= \left[4x + \frac{3x^2}{2} - \frac{x^3}{3}\right]_{-1}^{4}


At x=4x = 4:

4(4)+3(4)22−(4)334(4) + \frac{3(4)^2}{2} - \frac{(4)^3}{3}

=16+482−643= 16 + \frac{48}{2} - \frac{64}{3}

=16+24−643= 16 + 24 - \frac{64}{3}

=40−643= 40 - \frac{64}{3}

=1203−643= \frac{120}{3} - \frac{64}{3}

=563= \frac{56}{3}


At x=−1x = -1:

4(−1)+3(−1)22−(−1)334(-1) + \frac{3(-1)^2}{2} - \frac{(-1)^3}{3}

=−4+32+13= -4 + \frac{3}{2} + \frac{1}{3}

=−246+96+26= \frac{-24}{6} + \frac{9}{6} + \frac{2}{6}

=−136= \frac{-13}{6}


Area=563−(−136)\text{Area} = \frac{56}{3} - \left(\frac{-13}{6}\right)

=563+136= \frac{56}{3} + \frac{13}{6}

=1126+136= \frac{112}{6} + \frac{13}{6}

=1256= \frac{125}{6}

Therefore, the area bounded by the curve and the x-axis is 1256\dfrac{125}{6} square units.

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