Boundary Math Example 4

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Example 4

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The region RR is defined by the inequalities xโ‰ฅ0x \geq 0, yโ‰ฅ0y \geq 0, and x+yโ‰ค6x + y \leq 6. Describe the boundary of RR and find its perimeter.

Solution

  1. 1
    Step 1: The region is a triangle with vertices at (0,0)(0,0), (6,0)(6,0), and (0,6)(0,6).
  2. 2
    Step 2: The boundary consists of three line segments: the xx-axis from (0,0)(0,0) to (6,0)(6,0), the yy-axis from (0,0)(0,0) to (0,6)(0,6), and the line x+y=6x+y=6 from (6,0)(6,0) to (0,6)(0,6).
  3. 3
    Step 3: Lengths: xx-segment =6= 6, yy-segment =6= 6, hypotenuse =62+62=62= \sqrt{6^2+6^2} = 6\sqrt{2}. Perimeter =12+62โ‰ˆ20.49= 12 + 6\sqrt{2} \approx 20.49 units.

Answer

Triangular boundary with vertices (0,0)(0,0), (6,0)(6,0), (0,6)(0,6); perimeter =12+62โ‰ˆ20.49= 12 + 6\sqrt{2} \approx 20.49 units.
Inequalities define regions, and the boundary is formed by the edges where the inequalities become equalities. The boundary of this triangular region consists of the three line segments on which x=0x=0, y=0y=0, or x+y=6x+y=6.

About Boundary

The edge or outline that separates the interior of a region from its exterior; the set of points on the dividing border.

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