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Please solve RD Sharma Class 12 Chapter 20 Areas of Bounded Regions Exercise 20.3 Question 50 Maths textbook solution.

Answers (1)

Answer:

4 sq. units.

Hints:

Use concept of definite integrals.

Given:

The curves y=\left | x-1 \right |  and y=3-\left | x \right |

Solution:

To find area bounded by the curve

 

\begin{aligned} &y=|x-1|\\ &\Rightarrow y=\left\{\begin{array}{l} 1-x, \text { if } x<1 \; \; \; \; \; \; \; .......(1)\\ x-1, \text { if } x \geq 1\; \; \; \; \; \; \; ........(2)) \end{array}\right.\\ & \end{aligned}

And   y=3-\left | x \right |

\Rightarrow \quad y= \begin{cases}3+x, \text { if } x<0\; \; \; \; \; \; \; \; \; ......(3) \\ 3-x, \text { if } x \geq 0\; \; \; \; \; \; \; \; \; ......(4)\end{cases}

 

Drawing the rough sketch of lines (1), (2), (3) and (4) as under:

Shaded region is the required area

Required area = Region ABCDA

A = Region ABFA + Region AFCEA + Region CDEC

\begin{aligned} &=\int_{1}^{2}\left(y_{1}-y_{2}\right) d x+\int_{0}^{1}\left(y_{1}-y_{3}\right) d x+\int_{-1}^{0}\left(y_{4}-y_{3}\right) d x \\ &=\int_{1}^{2}(3-x-x+1) d x+\int_{0}^{1}(3-x-1+x) d x+\int_{-1}^{0}(3+x-1+x) d x \\ &=\int_{1}^{2}(4-2 x) d x+\int_{0}^{1} 2 d x+\int_{-1}^{0}(2+2 x) d x \\ &=\left[4-x^{2}\right]_{1}^{2}+[2 x]_{0}^{1}+\left[2 x+x^{2}\right]_{-1}^{0} \\ &=[(8-4)-(4-1)]+[2-0]+[(0)-(-2+1)] \\ &=(4-3)+2+1 \end{aligned}

A = 4 sq. units.

Therefore, the area bounded by the curve is 4 sq. units.

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