Question Details

The area bounded by the lines y = |x| – 1 and y = - |x| + 1 is

Options

A

1 sq. unit

B

2√2 sq. units

C

2 sq. units

D

4 sq. units

Correct Answer :

2 sq. units

Solution :

The correct option is "2 sq. units".

To find the area of the region bounded by the given lines, let us first write down the equations of the boundary lines:
Line 1: y=|x|1
Line 2: y=|x|+1

We can rewrite these equations by analyzing the behavior of the absolute value function |x| for different intervals of x:

For x0 (the right half of the coordinate plane):
Line 1 becomes: y=x1
Line 2 becomes: y=x+1

For x<0 (the left half of the coordinate plane):
Line 1 becomes: y=x1
Line 2 becomes: y=x+1

Now, let us find the intersection points of these boundary lines:
1. Intersection of y=x1 and y=x+1 (for x0):
Equating the two expressions for y:
x1=x+12x=2x=1
Substituting x=1 into either equation gives y=0. So, one vertex is (1,0).
2. Intersection of y=x1 and y=x+1 (for x<0):
Equating the two expressions:
x1=x+12x=2x=1
Substituting x=1 into either equation gives y=0. So, another vertex is (1,0).
3. Along the y-axis where x=0:
For Line 1, y=|0|1=1, giving the vertex (0,1).
For Line 2, y=|0|+1=1, giving the vertex (0,1).

Plotting these four points (1,0), (1,0), (0,1), and (0,1) on the coordinate plane and connecting them shows that the bounded region is a square (or a rhombus) whose diagonals lie along the coordinate axes.

Let us calculate the lengths of the diagonals:
Diagonal 1 (along the x-axis, from 1 to 1):
d1=1(1)=2 units
Diagonal 2 (along the y-axis, from 1 to 1):
d2=1(1)=2 units

The area of a quadrilateral with perpendicular diagonals is given by the formula:
Area=12×d1×d2
Substituting the diagonal lengths into this formula:
Area=12×2×2=2 sq. units

Thus, the area bounded by the given lines is 2 sq. units.

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