2023 AMC 10B Problems/Problem 13: Difference between revisions
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== Solution == | |||
First consider, <math>|x-1|+|y-1| <= 1.</math> | |||
We can see that it's a square with radius 1 (diagonal 2). The area of the square is <math>\sqrt{2}^2 = 2.</math> | |||
Next, we add one more absolute value and get <math>|x-1|+||y|-1| <= 1.</math> This will double the square reflecting over x-axis. | |||
So now we got 2 squares. | |||
Finally, we add one more absolute value and get <math>||x|-1|+||y|-1| <= 1.</math> This will double the squares reflecting over y-axis. | |||
In the end, we got 4 squares. The total area is <math>4\cdot2 = 8</math>. | |||
Revision as of 16:47, 15 November 2023
Solution
First consider,
We can see that it's a square with radius 1 (diagonal 2). The area of the square is
Next, we add one more absolute value and get
This will double the square reflecting over x-axis.
So now we got 2 squares.
Finally, we add one more absolute value and get
This will double the squares reflecting over y-axis.
In the end, we got 4 squares. The total area is
.