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Ex 4.2,1 (i) - Chapter 4 Class 12 Determinants
Last updated at August 21, 2026 by Teachoo
Chapter 4 Class 12 Determinants
Concept wise
- Finding determinant of a 2x2 matrix
- Evalute determinant of a 3x3 matrix
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Area of triangle
- Equation of line using determinant
- Finding Minors and cofactors
- Evaluating determinant using minor and co-factor
- Find adjoint of a matrix
- Finding Inverse of a matrix
- Inverse of two matrices and verifying properties
- Finding inverse when Equation of matrice given
- Checking consistency of equations
- Find solution of equations- Equations given
- Find solution of equations- Statement given
- Verifying properties of a determinant
- Two rows or columns same
- Whole row/column zero
- Whole row/column one
- Making whole row/column one and simplifying
- Proving Determinant 1 = Determinant 2
- Solving by simplifying det.
- Using Property 5 (Determinant as sum of two or more determinants)
Transcript
Ex 4.2, 1 Find area of the triangle with vertices at the point given in each of the following: (1, 0), (6, 0), (4, 3) The area of triangle is given by โ = ๐/๐ |โ 8(๐ฑ๐&๐ฒ๐&๐@๐ฑ๐&๐ฒ๐&๐@๐ฑ๐&๐ฒ๐&๐)| Here, x1 = 1 , y1 = 0 x2 = 6 ,y2 = 0 x3 = 4 ,y3 = 3 โ = ๐/๐ |โ 8(๐&๐&๐@๐&๐&๐@๐&๐&๐)| = 1/2 (1|โ 8(0&1@3&1)|โ0|โ 8(6&1@4&1)|+1|โ 8(6&0@4&3)|) = 1/2 (1(0 โ 3) โ 0(6 โ 4) + 1 (18 โ 0)) = 1/2 (1(โ3) + 0 + 1 (18) ) = 1/2 [โ3 + 18 ] = ๐๐/๐ Thus, the required area of triangle is ๐๐/๐ square units
