Matrix Trace Calculator

Calculate the trace of square matrices by summing diagonal elements

Matrix Input

Trace is only defined for square matrices

Matrix Elements

Diagonal elements are highlighted in purple. Enter decimal numbers (e.g., 0.5, -2.3)

Quick Examples

Matrix Trace Results

15
Matrix Trace
tr(A)
1 + 5 + 9
Diagonal Sum
3
Matrix Size
3×3

Matrix Properties

  • Diagonal Matrix:No
  • Identity Matrix:No
  • Symmetric Matrix:No

Trace Properties

Formula: tr(A) = a₁₁ + a₂₂ + ... + aₙₙ

Linear Property: tr(A + B) = tr(A) + tr(B)

Scalar Property: tr(kA) = k·tr(A)

Step-by-Step Calculation

1. Calculating trace of 3×3 matrix
2. Trace = sum of diagonal elements
3. a11 = 1
4. a22 = 5
5. a33 = 9
6. Trace = 1 + 5 + 9 = 15

Trace Analysis

✅ Positive trace (15) - Sum of diagonal elements is positive

Matrix Visualization

A =
1
2
3
4
5
6
7
8
9

Diagonal elements (trace components) are highlighted in purple

How to Calculate Trace

1

Identify Diagonal

Find elements where row = column

2

Sum Elements

Add all diagonal elements

3

Result

The sum is your matrix trace

Trace Properties

Linear: tr(A + B) = tr(A) + tr(B)

Scalar: tr(kA) = k·tr(A)

Cyclic: tr(AB) = tr(BA)

Transpose: tr(Aᵀ) = tr(A)

Eigenvalues: tr(A) = Σλᵢ

Identity: tr(I) = n

Understanding Matrix Trace

What is Matrix Trace?

The trace of a square matrix is the sum of all its diagonal elements. It's denoted as tr(A) and represents one of the most fundamental invariants of a matrix. The trace provides important information about the matrix's properties and its eigenvalues.

Formula

tr(A) = a₁₁ + a₂₂ + a₃₃ + ... + aₙₙ

Sum of diagonal elements from top-left to bottom-right

Important Properties

  • Linearity: The trace is a linear operator
  • Cyclicity: tr(ABC) = tr(BCA) = tr(CAB)
  • Invariance: tr(A) = tr(Aᵀ) for transpose
  • Eigenvalue Sum: tr(A) equals sum of eigenvalues

Applications

  • Eigenvalue calculations and characteristic polynomials
  • Matrix similarity and invariant theory
  • Linear algebra and differential geometry
  • Quantum mechanics and statistical mechanics