The area (in sq. units) of the region is:
- A
- B
- C
- D
The area (in sq. units) of the region is:
Correct answer:A
Standard Method
Given: The region is defined by
Find: The area of the region.
The region is symmetric about the -axis, so calculate the area for and multiply by .
For , the upper boundary is
Find the intersection points by equating the two curves:
Now compare the curves:
So the first-quadrant area is
Evaluate the integrals:
Using symmetry, total area is
Therefore, the correct option is A and the area is .
Symmetry and piecewise boundary
Given: The region lies below both and , above , with .
Find: The enclosed area.
Because both expressions involve or , the region is symmetric about the -axis. Hence,
In the first quadrant, , so the two upper curves become and . The relevant upper boundary is the smaller of these two curves.
Their intersection is obtained from
Thus, they meet at and .
So the area in the first quadrant is split into two parts:
The first integral is
The second integral is
Hence first-quadrant area is
Therefore, total area is
Therefore, the area of the region is .
Using the larger upper curve instead of the smaller one. The inequalities require to satisfy both upper bounds, so the correct ceiling is , not the maximum.
Forgetting symmetry about the -axis. If you integrate only for and do not multiply by , you get only half the required area.
Not splitting the integral at the intersection point . The lower of the two curves changes there, so one single integral over to is incorrect.
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