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Correct answer: 27
- Interpret the two regions
We are given and
We need the number of points in .
Since , the intersection consists of natural-number lattice points satisfying both inequalities.
- Rewrite the inequalities in standard form
For : Divide by :
So is the set of natural-number points inside/on the ellipse centered at with semi-axes and .
For : which is the disk centered at with radius .
- Find possible natural values of from the ellipse
From we must have Thus Since , possible values are
Now also impose the circle condition. Since the circle is centered at with radius , so all to are allowed in principle.
Hence we check each integer .
- For each , find allowed integer values
We need both
Because , we count natural-number satisfying both.
Let .
Case 1:
Ellipse:
So , hence
Circle: so
Thus for , count .
Case 2:
Ellipse: So , hence
Circle: So , giving
Common values: Count .
Case 3:
Ellipse: so
Circle: So , giving
Common values: Count .
Case 4:
Ellipse: so
Circle: so , hence
Common values: Count .
Case 5:
Ellipse: so
Circle: so , hence
Common values: Count .
Case 6:
Ellipse: So , hence
Circle: so , hence
Common values: Count .
Case 7:
Ellipse: so
Circle: so can be many values, but intersection gives only
Count .
- Add all counts
Total number of points is
Therefore,
- Comparison with stored answer
Stored correct answer:
Our derived answer is also , so it agrees.
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