What do these matrix symbols mean?

[eddysd]

The question just says "Calculate" followed by these:

a)
|a+b -b|
| b a-b|

b)
| 2 4-n|
| 1 2 |

c)
|0 a 0|
|0 0 b|
|c 0 0|

In the question the lines at the edges are joined up, but not brackets. I don't know what to calculate or how to do it. A worked example would be helpful!

 

[ehild]

These things between two vertical lines can be determinants. Look after, how to calculate the value of a determinant.

ehild

 

[eddysd]

So for part a) would the answer be: a^2 - 2b^2 ?

 

[ehild]

Not quite... You have to subtract (-b^2).

ehild

 

[eddysd]

oh yeah, woops, so it's actually just a^2?

 

[Mark44]

Yes.