Explanation
To find the area bounded by these curves, we need to identify the "upper" curve and the "lower" curves within the given interval x∈[0,2].
1. Identify the Boundaries
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Upper Boundary: The quadratic function yu=−x2+2x+4 is defined for the entire range x∈[0,2].
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Lower Boundary: This is split into two parts:
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From x=0 to x=1, the lower curve is yl1=x.
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From x=1 to x=2, the lower curve is yl2=x2.
2. Set up the Definite Integrals
The total area A is the integral of (Upper Curve - Lower Curve) over the specified intervals:
A=∫01[(−x2+2x+4)−x]dx+∫12[(−x2+2x+4)−x2]dx
3. Calculate the First Integral (I1)
For x∈[0,1]:
I1=∫01(−x2+2x+4−x1/2)dx
I1=[−3x3+x2+4x−32x3/2]01
I1=(−31+1+4−32)−0=4 sq. units
4. Calculate the Second Integral (I2)
For x∈[1,2]:
Substituting the limits:
I2=(−32(8)+4+8)−(−32+1+4)
I2=(−316+12)−(313)=320−313=37 sq. units
5. Total Area
Correct Option: (b) 319 sq. units