The area of the region bounded by the parabola (y – 2)2 =x – 1, the tangent to it at the point with the ordinate 3 and the x-axis is

The question describes something like –



To solve the problem, we need to find the points 1, 2, and 3 first. They are the key to setting up the bounds of our integration and understanding what function to integrate.


For point 1:-


We know it is a point on the parabola with ordinate 3, at which the tangent to the parabola is taken.


Plugging in y = 3 into the equation for the parabola (y – 2)2 = x – 1,


(3 – 2)2 = x – 1


1 = x – 1


x = 2


So, Point 1 is (2, 3)


For point 2:-


We need to find the point of intersection of the parabola and the x – axis.


We know that ordinate at this point is 0.


Plugging in y = 0 into the equation for the parabola (y – 2)2 = x – 1,


(0 – 2)2 = x – 1


4 = x – 1


x = 5


So, Point 2 is (5, 0)


For point 3:-


Tangent at any point (x1, y1) for a curve is –


y – y1 = (x – x1)


For parabola (y – 2)2 = x – 1, differentiating both sides of the equation –


2(y – 2) = 1



So, slope at point 1, i.e., (2, 3) is –



So, equation of tangent at (2, 3) is –


y – 3 = � (x – 2)


2y – 6 = x – 2


x – 2y + 4 = 0


The tangent intersects the x – axis at point 3. At this point, ordinate is 0.


So, plugging y = 0 in the equation of the tangent x – 2y + 4 = 0, -


x – 2 �0 + 4 = 0


x = -4


So, point 3 is (-4, 0).


Now, that we have the 3 points, let’s figure out how to compute the area required.


The area we need can be divided into 3 sections –


i. x = -4 to x = 1


Here, area required = area enclosed by the tangent and the x – axis


ii. x = 1 to x = 2


Here, area required = (area enclosed by the tangent and the x – axis) – (area enclosed within the parabola)


iii. x = 2 to x = 5


Here, area required = area enclosed by the parabola and the x – axis


The parabola is (y – 2)2 = x – 1


Solving for y,


y = 2 ± √(x – 1)


So, area A we need is –









(Ans)

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