CBSE Class 12 Mathematics Notes Chapter 8 Application of Integrals

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The application of integrals is used to calculate the area and volume of different 2-D and 3-D curves, and they have various applications in mathematics. 

  • They help us calculate the area of an arc of a circle, irregular boundaries, the volume of various curves, and the area between the two curves. 
  • Integrals include the summation of discrete data, and their applications cover basic integral concepts such as the fundamental theorem of calculus
  • It is used in the fields of architecture, electrical engineering, medical science and statistics.
  • In mathematics, integrals are used to calculate the area under a curve and the area of a region bounded by a curve and a line.

Application of integrals is important for class 12 students, as well as engineering mathematics. CBSE Class 12 Mathematics Notes for Chapter 8 Application of Integrals are given in the article below for easy preparation and understanding of the concepts involved.

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Application of Integrals

There are various applications of integrals. Some of them are as follows:

  • It is used to calculate the area under simple curves.
  • The concept is used to find areas enclosed by lines, arcs of circles, parabolas, and ellipses.
  • Integrals are used to find out the area between two curves.
  • It is used to find out the centroids of areas of the triangle with curved boundaries.
  • In the field of statistics, it is used to determine survey data to improve marketing plans for different companies.

Area Between the Curve and the Axis

  • The area of the region bounded by the curve y = f(x), x-axis, and the lines x = a and x = b (b > a) is given by the formula

Area = ∫ab y dx = ∫ab f(x) dx

The area between the curve and the axis

The area between the curve and the axis

  • The area of the region bounded by the curve x = Φ(y), y-axis, and the lines y = c and y = d (b > a) is given by the formula

Area = ∫cd x dy = ∫cd Φ(y) dy


Area Between Two Curve

  • The area of the region enclosed between two curves y = f(x), y = g(x), and the lines x = a, x = b is given by the formula

Area = ∫ab [f(x) - g(x)] dx

Where f(x) ≥ g (x) in [a, b]

Area Between Two Curve

Area Between Two Curve

  • If f(x) ≥ g (x) in [a, c] and f(x) ≤ g (x) in [c, b], a < c < b, then

Area = ∫ac [f(x) - g(x)] dx + ∫cb [g(x) - f(x)] dx


Method to Find Area Under Curve

  • To calculate area, first, find the equation of the curve, y = f(x), as well as its limits and axis.
  • The integration i.e. antiderivative of the curve is found.
  • The upper and lower limits are applied to the integral result, and the difference provides the area under the curve.

Area in Polar Coordinates

  • Consider the region OKM bounded by a polar curve r = f(θ) and two semi-straight lines θ = ⍺ and θ = ꞵ.
  • The area of the polar region is given by

Area = 1/2 ∫ r2 dθ = 1/2 ∫ f2(θ) dθ

Area in Polar Coordinates

Area in Polar Coordinates


Area Between Two Polar Curves

  • The area of a region between two polar curves r = f(θ) and r = g(θ) in the sector [⍺, ꞵ] is expressed by the integral

Area = 1/2 ∫ [f2(θ) – g2(θ)] dθ

Area Between Two Polar Curves

Area Between Two Polar Curves


Some Standard Curves and their Equation

  • Straight Line:

x = a and x = – a, where a > 0

Straight Line

Straight Line

  • Circle:

x2 + y2 = a2

Circle

Circle

  • Parabola:

y2 = 4ax or y2 = – 4ax

Parabola

Parabola

  • Ellipse

x2/a2 + y2/b2 = 1

Ellipse

Ellipse

There are Some important List Of Top Mathematics Questions On Applications Of Integrals Asked In CBSE CLASS XII

CBSE CLASS XII Related Questions

  • 1.
    Obtain the value of \[ \Delta = \begin{vmatrix} 1 + x & 1 & 1 \\ 1 & 1 + y & 1 \\ 1 & 1 & 1 + z \end{vmatrix} \] in terms of \(x, y, z\). Further, if \(\Delta = 0\) and \(x, y, z\) are non–zero real numbers, prove that \[ x^{-1} + y^{-1} + z^{-1} = -1 \]


      • 2.

        A rectangle of perimeter \(24\) cm is revolved along one of its sides to sweep out a cylinder of maximum volume. Find the dimensions of the rectangle. 


          • 3.
            Find the general solution of the differential equation \[ y\log y\,\frac{dx}{dy}+x=\frac{2}{y}. \]


              • 4.
                Mother, Father and Son line up at random for a family picture. Let events \(E\): Son on one end and \(F\): Father in the middle. Find \(P(E/F)\).


                  • 5.
                    If \[ P = \begin{bmatrix} 1 & -1 & 0 \\ 2 & 3 & 4 \\ 0 & 1 & 2 \end{bmatrix} \quad \text{and} \quad Q = \begin{bmatrix} 2 & 2 & -4 \\ -4 & 2 & -4 \\ 1 & -1 & 5 \end{bmatrix} \] find \( QP \) and hence solve the following system of equations using matrix method:
                    \[ x - y = 3,\quad 2x + 3y + 4z = 13,\quad y + 2z = 7 \]


                      • 6.
                        A line passing through the points \(A(1,2,3)\) and \(B(6,8,11)\) intersects the line \[ \vec r = 4\hat i + \hat j + \lambda(6\hat i + 2\hat j + \hat k) \] Find the coordinates of the point of intersection. Hence write the equation of a line passing through the point of intersection and perpendicular to both the lines.

                          CBSE CLASS XII Previous Year Papers

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