Find the area of the region bound by the curves y = 6x - x2 and y

Sketch the graphs of the curve y2 = x and y= 4 - 3x and find the area enclosed between them.


y2 = 4 - 3x    ...(i)

y2 = x         ...(ii)

Solving equation (i) and (ii), we get

4x = 4, x = 1

Required Area = 

                      = 2x3/23201 +4 - 3x3/23/2 13143

                     =  2132 + 4 - 3 × 433/23/2 - 4 - 33/23/213

                     = 223 + 23 × 13

                     = 22/3 + 2/9

                     = 16/9 sq. units.

 


Find the smaller area enclosed by the circle x2 + y2 and the line x + y = 2.


The required area = 024 - x2dx - 022 - xdx

                           = x24 - x2 + 42sin-1x202 - 2x - x2202

                           = 1 × 0 + 2 sin-11 - 04 - 2 × 0 - 2 ×2 - 42 - 2 × 0 + 02

                           = 2sin-11 + 4 - 2 - 0 + 0

                           = 2 × π2 - 2

                           = π - 2 sq. units.


Find the area bounded by the curve y = 2x - x2, and the line y = x


Solving, x = y, y = 2x - x2,

2x - x2 = x

x2 - x = 0

x(x - 1) = 0

x = 0, 1

Required Area = 01y1 - y2dx

                     = 012x - x2 - x2dx

                     = 01x - x2dx

                    = x22 - x3301

                    = 12 - 13 - (0) = 16 sq. units


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Find the area of the region bound by the curves y = 6x - x2 and y - x2 - 2x.


The curve y = 6x - x2

Therefore, y = -(x - 3)2 + 9 

y = -(x - 3)2 + 9 represents parabola with vertex at (3, 9) and it opens downward.

The curve y = x2 - 2x = (x - 1)2 - 1

y = (x - 1)2 - 1 represents a parabola with vertex at (1, - 1) and it opens upward.

Both the curves pass through origin and intersect in the first quadrant at (4, 8)

Required area = 04(6x - x2)dx - 04(x2 - 2x)dx

                     = 04(8x - 2x2).dx

                    = 8.x22 - 2.x3304

                    = 64 - 1283

                    = 643 sq. units


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