**Author** |
**Message** |

**charles1118** Regular poster
Post Number: 37
| Posted on Sunday, 20 January, 2013 - 04:17 pm: | |
I find this difficult for my homework. Can i ask for extra help? |

**Emma McCaughan** Moderator
Post Number: 4848
| Posted on Sunday, 20 January, 2013 - 05:06 pm: | |
Whether you are allowed, I don't know - that depends on the rules of your institution. (It's probably okay unless the homework counts towards formal assessment. And our team will give you hints to help you solve it yourself, rather than doing it for you.) For (a), you've been asked to verify, rather than derive. What would be a good way to check whether those inverse matrices are correct? |

**charles1118** Regular poster
Post Number: 38
| Posted on Monday, 21 January, 2013 - 03:29 pm: | |
This is a normal homework towards formal assessment. Thanks for you help. For the verification, you mean by subsitution?? Thanks˜˜˜ |

**Arun Iyer** Veteran poster
Post Number: 1300
| Posted on Monday, 21 January, 2013 - 05:02 pm: | |
If somebody gives you a matrix B and claims that it is inverse of A, what is way to verify that B truly is the inverse of A? |

**charles1118** Regular poster
Post Number: 39
| Posted on Tuesday, 22 January, 2013 - 03:09 pm: | |
A A(-1) =I ???? as A(-1) is unique??? sorry i am no good in maths... |

**charles1118** Regular poster
Post Number: 40
| Posted on Tuesday, 22 January, 2013 - 03:36 pm: | |
A X A(-1) = I use this theorem to verify??? |

**Arun Iyer** Veteran poster
Post Number: 1301
| Posted on Wednesday, 23 January, 2013 - 12:35 am: | |
Right. |

**charles1118** Regular poster
Post Number: 41
| Posted on Sunday, 27 January, 2013 - 04:39 am: | |
Thanks all. I have solved it˜˜˜˜˜ |