Notation for sum of roots etc? (1 Viewer)

[QZP]

I was looking at 4u solutions of Terry Lee and noticed he did "Σ a" to denote sum of single roots and furthermore "Σ ab" to denote sum of products of two roots at a time, etc.
I.e. Σ a = -b/a
Σ ab = c/a
.
.
.

How valid is this in 3u? I always wrote out in words "by sum of single roots" :S

 

[timeflies]

For Extension 2, I believe you are allowed to use this notation in working but should not leave your final answer like this.
So at the end you must say a + b = ... not sigma a = ... and so forth

 

[asianese]

It is valid by all means.

Even though it is used less, it doesn't discredit it at all. Simga/Pi notation is used throughout maths so don't be afraid to use it.

 

[Carrotsticks]

I personally use Sigma_i or Sigma_{i<j} but when I used to write it out in English, I used 'sum of roots' and 'sum in pairs'

 

[QZP]

It is valid by all means.

Even though it is used less, it doesn't discredit it at all. Simga/Pi notation is used throughout maths so don't be afraid to use it.

That last one means product of all the single roots right?

 

[asianese]

That's correct.