- A
- B
- C
- D
View written solutionFree
Correct answer: C
- Interpret the region
We need the area of
The inequalities imply:
So the region lies:
- above the curve ,
- to the right of the line ,
- to the left of the line .
- Rewrite the curve in terms of
Since we have the equivalent condition
Thus:
- for , ,
- for , .
But using horizontal strips is more convenient because of the line .
From we get so
Hence for a fixed , the curve allows
The line condition gives
Therefore, for each , the allowed -interval is the intersection
- Find the range of
Since , from the curve condition we must have at least some satisfying .
Also, from , we get
And clearly because .
So .
Now determine where the intersection is nonempty.
For fixed , the right endpoint of curve interval is , and the left endpoint from the line is . We need That is,
Since , this gives The single point contributes zero area, so effectively .
Also, for , note that so the right boundary is , not .
Thus the horizontal width is
- Integrate to get the area
Therefore,
Compute:
This seems too large, so let us check carefully.
Actually,
so
But this contradicts the options, so let us re-check the interval intersection.
- Correct interpretation of the region
The condition is Since the right-hand side is nonnegative, this means the region is above the curve. For a fixed , points above the curve satisfy
so indeed
That part is correct.
Now combine with
This is
So the actual width is
For :
- , so right end is .
- Compare and :
Hence:
- for , , so left end is ;
- for , , so left end is .
So we must split the integral.
- Compute area in two parts
For
Width:
Area contribution:
For
Width:
Area contribution:
Now,
At :
At :
Thus,
Hence total area:
- Match with options
So the correct option is C.
- Compare with stored correct answer
Stored correct answer: C
Our derived answer: C
They agree.
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