CBSE Class 12 Math 2013 Solved Paper
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Question : 25 of 29
Marks:
+1,
-0
Using integration, find the area bounded by the curve = 4y and the line x = 4y – 2.
OR
Using integration, find the area of the region enclosed between the two circles
= 4 and = 4.
OR
Using integration, find the area of the region enclosed between the two circles
= 4 and = 4.
Solution:
The shaded area OBAO represents the area bounded by the curve = 4y and line x = 4y – 2.
Let A and B be the points of intersection of the line and parabola.
Co-ordinates of point A are . Co-ordinates of point B are (2, 1).
Area OBAO = Area OBCO + Area OACO … (1)
Area OBCO = dx - dx
= -
= (2 + 4) -
= =
Area OACO = dx - dx
= -
= -
= -
= =
Therefore, required area = = sq. units
OR
Given equations of the circles are
= 4 ... (1)
= 4 ... (2)
Equation (1) is a circle with centre O at the origin and radius 2. Equation (2) is a circle with centre C (2, 0) and radius 2.
Solving (1) and (2), we have:
=
- 4x + 4 + =
x = 1
This gives y =
Thus, the points of intersection of the given circles are A (1 , and A' (1 , - ) as shown in the figure.
Required area
= Area of the region OACA'O
= 2 [area of the region ODCAO]
= 2 [area of the region ODAO + area of the region DCAD]
= 2
= 2 [ dx + dx]
= 2 +
= +
= +
= - 2
Let A and B be the points of intersection of the line and parabola.
Co-ordinates of point A are . Co-ordinates of point B are (2, 1).
Area OBAO = Area OBCO + Area OACO … (1)
Area OBCO = dx - dx
= -
= (2 + 4) -
= =
Area OACO = dx - dx
= -
= -
= -
= =
Therefore, required area = = sq. units
OR
Given equations of the circles are
= 4 ... (1)
= 4 ... (2)
Equation (1) is a circle with centre O at the origin and radius 2. Equation (2) is a circle with centre C (2, 0) and radius 2.
Solving (1) and (2), we have:
=
- 4x + 4 + =
x = 1
This gives y =
Thus, the points of intersection of the given circles are A (1 , and A' (1 , - ) as shown in the figure.
Required area
= Area of the region OACA'O
= 2 [area of the region ODCAO]
= 2 [area of the region ODAO + area of the region DCAD]
= 2
= 2 [ dx + dx]
= 2 +
= +
= +
= - 2
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