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.

    At a birthday party, children are being served orange juice in conical cups, as shown in the figure. 


    Each cup is 15 cm deep and has a radius 5 cm. The juice is being poured into this cup at a rate of 0·1 cm3/s.
    On the basis of the above information, answer the following questions :


      • 2.
        Find:

        The shortest distance between the lines: \[ \vec{r}=(4+\lambda)\hat{i}+(2\lambda-1)\hat{j}-3\lambda\hat{k} \] and \[ \vec{r}=(1+2\mu)\hat{i}+(4\mu-1)\hat{j}+(2-5\mu)\hat{k} \]


          • 3.

            A carpenter needs to design a wooden box in the shape of a cuboid such that the sum of its length and breadth is 3 cm more than its height. Twice of its length, thrice of its breadth and its height add up to 10 cm. Its breadth added to 7 times its height is 1 cm less than 3 times its length. 


              • 4.
                Find:

                If \[ (3\hat{i}-2\hat{j}+5\hat{k})\times(4\hat{i}+p\hat{j}+q\hat{k})=\vec{0} \] then find the values of \(p\) and \(q\).

                  • \(p = -\frac{2}{3}, \, q = \frac{5}{3}\)
                  • \(p = -\frac{8}{3}, \, q = \frac{20}{3}\)
                  • \(p = \frac{20}{3}, \, q = -\frac{8}{3}\)
                  • \(p = 0, \, q = 0\)

                • 5.
                  Which of the following equations is NOT a Linear Differential Equation?

                    • \((1 + x^2) \, dy + 2xy \, dx = \cot x \, dx\)
                    • \(y + \frac{d}{dx}(xy) = x(\sin x + \log x)\)
                    • \(x(1 + y^2) \, dx - y(1 + x^2) \, dy = 0\)
                    • \(y \, dx - (x + 3y^2) \, dy = 0\)

                  • 6.
                    Find: \[ \int \frac{x^2}{(x^2-1)(x^2+4)}\,dx \]

                      CBSE CLASS XII Previous Year Papers

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