The inverse of A = \pmatrix{ a & b \cr c & d} is
A^{-1} = \displaystyle \frac{1}{ad-bc} \pmatrix{ d & -b \cr -c & a }

Remember that in general AB \ne BA

Remember that in general AB \ne BA

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## This question appears in the following syllabi:

Syllabus | Module | Section | Topic | Exam Year |
---|---|---|---|---|

AQA A-Level (UK - Pre-2017) | FP4 | Matrix algebra | The basics | - |

AQA AS Further Maths 2017 | Pure Maths | Matrix Determinants and Inverses | Matrix Equations | - |

AQA AS/A2 Further Maths 2017 | Pure Maths | Matrix Determinants and Inverses | Matrix Equations | - |

CBSE XII (India) | Algebra | Matrices | Types, zero, identity, symmetric and skew symmetric | - |

CCEA A-Level (NI) | FP1 | Matrix algebra | The basics | - |

Edexcel A-Level (UK - Pre-2017) | FP1 | Matrix algebra | The basics | - |

Edexcel AS Further Maths 2017 | Core Pure Maths | Matrices | Matrix Equations | - |

Edexcel AS/A2 Further Maths 2017 | Core Pure Maths | Matrices | Matrix Equations | - |

Methods (UK) | M5 | Matrix algebra | The basics | - |

OCR A-Level (UK - Pre-2017) | FP1 | Matrix algebra | The basics | - |

OCR AS Further Maths 2017 | Pure Core | Determinants, Inverses and Equations | Matrix Equations | - |

OCR MEI AS Further Maths 2017 | Core Pure A | Determinants and Inverses | Matrix Equations | - |

OCR-MEI A-Level (UK - Pre-2017) | FP1 | Matrix algebra | The basics | - |

Pre-Calculus (US) | E2 | Matrix algebra | The basics | - |

Scottish Advanced Highers | M3 | Matrix algebra | The basics | - |

Scottish (Highers + Advanced) | AM3 | Matrix algebra | The basics | - |

Universal (all site questions) | M | Matrix algebra | The basics | - |

WJEC A-Level (Wales) | FP1 | Matrix algebra | The basics | - |