Mathematics Question Thread

[gilliesb18]

Thanks heaps for that!!! Very kind....

[caitlinlddouglas]

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\begin{align*}PA^2&=PB^2\\ (x-x)^2+\left(y - \frac{1}{3}(2+4x)\right)^2&= (x-x)^2 + \left(y-\frac14(7-3x)\right)^2\end{align*}
\[ \text{These will give the same equations as above.} \]

Hi was looking at this question and I was wondering why there only has to be 2 cases? Wouldn't there be 4 as you'd need to have one case positive, the other negative
Then both cases positive and both cases negative?
Thanks!

[RuiAce]

Hi was looking at this question and I was wondering why there only has to be 2 cases? Wouldn't there be 4 as you'd need to have one case positive, the other negative
Then both cases positive and both cases negative?
Thanks!

Because when you take all four cases, you will realise that some of the cases coincide.

[jamonwindeyer]

Because when you take all four cases, you will realise that some of the cases coincide.

To expand on that, consider the case:



Multiply by \(-1\) on both sides:



Similarly, we can turn \(A=-B\), into \(-A=B\) if we need to - So it is actually only two cases, though it can be written in four ways

[georgiia]

Am I allowed to use a pen to dram a set of axes on the exams paper and then graph in pencil so that If i needed to rub out the axes wouldn't rub out? Or is this not allowed :/
Also if it says "copy into your writing book" can I use pen?
Thanks!!

[RuiAce]

Am I allowed to use a pen to dram a set of axes on the exams paper and then graph in pencil so that If i needed to rub out the axes wouldn't rub out? Or is this not allowed :/
Also if it says "copy into your writing book" can I use pen?
Thanks!!

At the end of the day everything should be in pen. If you used pencil, you're ultimately going to have to trace over it in pen.

[georgiia]

At the end of the day everything should be in pen. If you used pencil, you're ultimately going to have to trace over it in pen.

Arn't graphs meant to be in pencil?

[RuiAce]

Arn't graphs meant to be in pencil?

Nope.

(Graphs used to be allowed in pencil. But then for some reason they changed their scanning system and it's now terrible. Pencil will most likely not get picked up by it unless it's a very dark one (4B+).)

[georgiia]

Nope.

(Graphs used to be allowed in pencil. But then for some reason they changed their scanning system and it's now terrible. Pencil will most likely not get picked up by it unless it's a very dark one (4B+).)

Oh wow ok lucky i asked bc in all my internals marks were deducted if you used pen

[winstondarmawan]

For a question like the one below where the question asks you to round in an earlier step:
https://scontent-syd2-1.xx.fbcdn.net/v/t35.0-12/22643316_1354494134676106_1428485746_o.png?oh=a4b3b3b16bd432cdaa3c24ae1adb3b22&oe=59EB0985
Would it be better to use the rounded value in the next steps or store the unrounded and use that?

[georgiia]

For a question like the one below where the question asks you to round in an earlier step:
https://scontent-syd2-1.xx.fbcdn.net/v/t35.0-12/22643316_1354494134676106_1428485746_o.png?oh=a4b3b3b16bd432cdaa3c24ae1adb3b22&oe=59EB0985
Would it be better to use the rounded value in the next steps or store the unrounded and use that?

I usually store it in the calculator because when you need to find the time later then you sub the calc value in and gove the time to the nearest second, min, hour whatever is asked.
Hope that helps

[Mymy409]

A little help with part 2 of this, please. Thanks in advance.


Sorry, the part that's cut off says 'Claire's path' and the corner that's cut off is labelled F and is the farmhouse.

[pokemonlv10]

I know one method for this is to graph it and calculate the area of the two triangles. Is there another method through integrating the absolute values? Do i consider cases?

[asahyoun3]

I know one method for this is to graph it and calculate the area of the two triangles. Is there another method through integrating the absolute values? Do i consider cases?

For this question, it is best to solve it graphically, as its more likely to make mistakes doing it algebraically

[pokemonlv10]

For this question, it is best to solve it graphically, as its more likely to make mistakes doing it algebraically

Is there a chance of them asking to integrate absolute values in the exam (Not in MC)? Because i would like to know the algebraic method