행렬식 계산기 로고
행렬식 계산기

행렬식 계산기

값을 입력하면 결과가 즉시 업데이트됩니다. 2×2~6×6 지원.

마지막으로 편집한 셀: a[1,1]

What is a determinant?

A determinant is a special scalar value calculated from a square matrix. It tells you if the matrix is invertible, how it scales areas/volumes, and encodes orientation. A zero determinant means the matrix is singular (non-invertible).

일반 공식

라이프니츠 공식: det(A) = Σσ sgn(σ) Πi ai,σ(i). 실제 계산에서는 효율을 위해 소거/분해를 사용합니다.

2×2, 3×3, 4×4

2×2: det([[a,b],[c,d]]) = ad − bc.

3×3:

4×4: 여인수 전개 또는 LU를 사용하세요. 이 계산기는 내부적으로 LU를 사용합니다.

성질

  • det(AB) = det(A)·det(B)
  • det(Aᵀ) = det(A)
  • 두 행을 바꾸면 → 부호가 바뀜
  • 한 행을 k배 → 행렬식도 k배

Understanding Determinants

A complete guide to one of the most important concepts in linear algebra

What is a Determinant?

A determinant is a special scalar value that can be calculated from any square matrix (a matrix with equal rows and columns). Written as det(A) or |A|, it encapsulates fundamental properties of the matrix in a single number.

The determinant tells you whether a system of linear equations has a unique solution, whether a matrix can be inverted, and how transformations affect geometric objects like area and volume.

Geometric Interpretation

2D: Area Scaling

The absolute value of a 2×2 determinant equals the area of the parallelogram formed by the row vectors.

3D: Volume Scaling

For 3×3 matrices, the determinant represents the volume of the parallelepiped spanned by the row vectors.

Sign = Orientation

Positive determinant preserves orientation; negative means reflection. Zero means the space is "flattened."

Why Determinants Matter

📊

Solving Linear Systems

Cramer's Rule uses determinants to solve systems of equations. If det ≠ 0, a unique solution exists.

🔄

Matrix Invertibility

A matrix has an inverse if and only if its determinant is non-zero. This is fundamental in linear algebra.

📐

Eigenvalue Problems

Finding eigenvalues requires solving det(A − λI) = 0, essential in physics and engineering.

🌐

Computer Graphics

Transformations in 3D graphics use matrices. The determinant reveals if shapes are flipped or scaled.

Zero vs Non-Zero Determinant

det(A) ≠ 0

  • Matrix is invertible
  • Rows/columns are linearly independent
  • System Ax = b has unique solution
  • Full rank matrix

det(A) = 0

  • Matrix is singular (non-invertible)
  • Rows/columns are dependent
  • System has no or infinite solutions
  • Rank deficient matrix

빠른 설명

See It In Action

Watch how determinants are calculated step-by-step with interactive examples

2×2 Matrix
3
8
4
6
=
-14
3×68×4 = -14
3×3 Sarrus Rule
1
2
3
4
5
6
7
8
9
=
0
Singular matrix (det = 0)
Identity Matrix
1
0
0
0
1
0
0
0
1
=
1
Identity always = 1

Interactive Step-by-Step: 2×2 Determinant

Step 1
Start with matrix
a b c d
Step 2
Multiply diagonals
a × d = ad
b × c = bc
Step 3
Subtract products
ad bc
Result
Determinant
det(A)
= ad − bc

Instant Results

Calculations update in real-time as you type

Flexible Sizes

Support for 2×2 up to 6×6 matrices

Step Breakdown

See the calculation process explained

Easy Export

Copy results or matrices with one click

행렬식 계산기 작동 방식

입력을 분석해 실시간으로 행렬식을 계산합니다. 수치 안정성과 성능을 위해 부분 피벗팅 LU 분해를 사용합니다. 결과는 U의 대각 원소의 곱에 행 교환으로 인한 부호를 곱한 값입니다.

자주 묻는 질문

1행렬식이란?
정방행렬에서 계산되는 스칼라 값입니다. 기하적으로는 면적/부피의 스케일과 방향을 나타냅니다. 행렬식이 0이면 행렬은 특이(역행렬 없음)입니다.
2일반 공식
라이프니츠 공식: det(A) = Σσ sgn(σ) Πi a_{i,σ(i)}. 실제 계산에서는 효율을 위해 소거/분해를 사용합니다.