help...

[onerealsmartass]

GEo&TRig:
With quesitons that ask 'what fraction of the volume did the rain occupy?'
Why is that we square rather than cube? <<pre noob question considering it says in the answers because the length remains constant.. lol but need some reassurance cant trust these trials.. AND would we do this in the actual exam?


Matrices:
When a question asks you to use a scalar matric for instance. 'the price is increased by 10%'
then is it better to show ur working as 1.1 X [ a b c]    OR      [1.1  0]  X   [a b c]
                                                             [ d e f]              [0  1.1]      [d e f]
thanks i learnt matrices myself so there are a few areas where i need help :/

[_avO]

Matrix form for percentage increases/decreases

[onerealsmartass]

okay thanks, cos in a trial paper it just had k X the matrix and i was like is that sufficient working to get the marks? lol

[plato]

GEo&TRig:
With quesitons that ask 'what fraction of the volume did the rain occupy?'
Why is that we square rather than cube? <<pre noob question considering it says in the answers because the length remains constant.. lol but need some reassurance cant trust these trials.. AND would we do this in the actual exam?

I assume you mean that a width and a height have both changed by the same fixed percentage (say 50%) but the length has not changed at all. If that is the case, then the (let's assume a box), the new volume is found by

(orig length) x [(orig width) x 1.5] x [(orig height) x 1.5]
This is the same as
[(orig length) x (orig width) x (orig height)] x 1.5^2
and this is the same as
[orig volume] x 1.5^2 and so, as you thought, you square here rather than cube.

There has been a question like this in the past that related to a triangular prism. While that is not a box, the principal is still the same if one of the dimensions (length, widt or height) remains constant.

If TWO of these remain constant, then just use a power of 1. For the box above, let's say that only the length increase by 50%, then the New Volume = [orig volume] x 1.5

**EDIT - separated your quote from my response

[onerealsmartass]

thanks
i just hope we dont get a quesiton like this...

[plato]

Matrices:
When a question asks you to use a scalar matric for instance. 'the price is increased by 10%'
then is it better to show ur working as 1.1 X [ a b c]    OR      [1.1  0]  X   [a b c]
                                                             [ d e f]              [0  1.1]      [d e f]
thanks i learnt matrices myself so there are a few areas where i need help :/

I am not sure what you mean by "scalar matrix" as these two words in further maths refer to numbers written in different ways.
In your first example:

the 1.1 is a "scalar" and the rest is a "matrix"

In your second example:

both are matrices.

Both of your calculations will give the same result and so, if you are asking what is the best way to write the product, it really depends on the way the question is written.