quick question on vectors, hl maths

muffinz

if i leave out those arrows above the letters will i lose marks? they are so time consuming and useless!!

johnmcdnl

muffinz wrote: »

if i leave out those arrows above the letters will i lose marks? they are so time consuming and useless!!

according to my teacher you can... what i do is on the very first like let J = j(arrow) and I = i(arrow)... then just remember to fill back in the answer line...

EuropeanSon

Not sure, tbh. I'd definitely put them in the final answer, even if you left them out in the workings. That'd probably be enough, though as I said, I'm not sure.

**Timbuk2**

The old way vectors were done was not with arrows, but they used to represent them like this

Let (a, b) be the vector, w.r.t. i and j (with the arrows), and then vectors are displayed like that from then on

For example 3i + 4j = (3, 4).

You could try that - make sure to state w.r.t (with respect to) i, j

LadyGaga!

My teacher said that you don't but to put them back in the final line incase the marking scheme changes. There's also nothing in past marking schemes noting that marks will be lost so I assume she's right.

muffinz

ah ok, thanks everyone

MathsManiac

By the way, have your teachers told you that the notation in the vectors question will be a bit different this year, arising from the new log tables and the fact that capital letters are now being used to represent points?

See the example in the SEC's letter to schools about this:
http://www.examinations.ie/schools/S_60_09_Information_re_Formulae_and_Booklet_Tables.pdf

In particular, at the top of the third page, they show you what last year's question 2(b) would look like in this year's notation.

(Vectors from a point to a point will have two capital letters with an arrow, but when the vector is represented by a single letter, it's a small letter with an arrow.)

muffinz

MathsManiac wrote: »

By the way, have your teachers told you that the notation in the vectors question will be a bit different this year, arising from the new log tables and the fact that capital letters are now being used to represent points?

See the example in the SEC's letter to schools about this:
http://www.examinations.ie/schools/S_60_09_Information_re_Formulae_and_Booklet_Tables.pdf

In particular, at the top of the third page, they show you what last year's question 2(b) would look like in this year's notation.

(Vectors from a point to a point will have two capital letters with an arrow, but when the vector is represented by a single letter, it's a small letter with an arrow.)

Omgosh thank you for telling me this, i had no idea!!

See how in that question, the Q is the point, but the q-> is really OQ? Am i getting that right?

MathsManiac

muffinz wrote: »

Omgosh thank you for telling me this, i had no idea!!

See how in that question, the Q is the point, but the q-> is really OQ? Am i getting that right?

Correct, the small letter q with an arrow represents the vector from the origin to capital Q.

It's also in the tables on the geometry page, where it shows you that the small letter a with an arrow represents OA (with an arrow).