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.
    If $y\sqrt{x^2 + 1} = \log\left(\sqrt{x^2 + 1} - x\right)$, show that: \[ (x^2 + 1)\frac{dy}{dx} + xy + 1 = 0 \]


      • 2.
        Find the coordinates of the foot of the perpendicular drawn from the point $(0, 2, 3)$ onto the spatial line given by: \[ \frac{-x-3}{-5} = \frac{1-y}{-2} = \frac{3z+12}{9} \] And hence, find the exact geometric length of this perpendicular line segment.


          • 3.
            If \[ 3P(A)=P(B)=\frac{3}{5} \] and \[ P(A\mid B)=\frac{2}{3}, \] then \[ P(A\cup B) \] is:

              • \( \frac{3}{5} \)
              • \( \frac{1}{5} \)
              • \( \frac{2}{15} \)
              • \( \frac{2}{5} \)

            • 4.
              Find the derivative of the composite algebraic-trigonometric function expression with respect to $x$: \[ f(x) = x^{\cot x} + \frac{2x^2 - 3}{2x^2 - x + 2} \]


                • 5.
                  Evaluate the definite integral:
                  \[ \int_{0}^{1} \frac{1}{x^2 + 2x + 3} \, dx \]


                    • 6.
                      Let three toys A, B and C be placed in the same straight line. If the position vectors of A, B and C are $55\hat{i} - 2\hat{j}$, $5\hat{i} + 8\hat{j}$ and $a\hat{i} - 52\hat{j}$ respectively, find the exact numerical value of '$a$'.

                        CBSE CLASS XII Previous Year Papers

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