VCE Maths questions help (2 Viewers)

boredsatan · Oct 13, 2017

But why is gst 1/11 when it said 10% gst?

BLIT2014 · Oct 13, 2017

boredsatan said:
But why is gst 1/11 when it said 10% gst?

GST is an additional 10% on top of the actual cost of an item.

Therefore, we need to find the original cost (which represents 100%) and 10% that has been placed "on top".

We could also work out it like this 10(gst)/ 110(total gst and cost of original item percent ) * price inclusive of GST
10/110 simplifies down to 1/10

BLIT2014 · Oct 13, 2017

boredsatan said:
But why is gst 1/11 when it said 10% gst?

If its price exclusive of GST to find GST we go -> price exclusive of GST * 1/10

boredsatan · Oct 14, 2017

The original hourly rate was $68 for 1 hour (with 10% gst included)
If the hourly rate was increased by 8.5%, calculate the new hourly rate (with gst included)
Is the answer $73.8?
Or do I need to include 10% extra gst?

boredsatan · Oct 14, 2017

boredsatan said:
The original hourly rate was $68 for 1 hour (with 10% gst included)
If the hourly rate was increased by 8.5%, calculate the new hourly rate (with gst included)
Is the answer $73.8?
Or do I need to include 10% extra gst?

Anyone?

BlackJoe · Oct 17, 2017

boredsatan said:
The original hourly rate was $68 for 1 hour (with 10% gst included)
If the hourly rate was increased by 8.5%, calculate the new hourly rate (with gst included)
Is the answer $73.8?
Or do I need to include 10% extra gst?

If you actually read the question, you will know that you don't need to worry about GST.
Ye, the answer is $73.8!

Judging from the history of this thread, that is a valid implication but have you considered,

extreme social anxiety
extreme sensitivity to judgement
can't accept the fact he is using his friends
mentally disabled friends
no friends
does not undertake secondary education (e.g. homeschooled)

boredsatan · Oct 17, 2017

Well obviously since that question appeared on a test and i haven't got my score back, i can't ask my teacher the answer

InteGrand · Oct 17, 2017

boredsatan said:
Well obviously since that question appeared on a test and i haven't got my score back, i can't ask my teacher the answer

Did you try asking your teacher? Also, I don't think you told us before that that question appeared on a test and you haven't got your score back, so it wasn't ''obvious''.

BlackJoe · Oct 18, 2017

After carefully re-examining this entire thread, you look very suspicious, boredsatan. Even more suspicious because of the origin of your avatar.

Given that you've been exposed to calculus, how can you not do a simple GST problem? It's like you've left every stone unturned or maybe you're trolling (Squar3root's theory)?

What's the cause of this discrepancy? I think the user He-Mann explained it very well and it might have removed the possibility of you trolling. Just maybe.

Late June, 2017. After getting 'told-off' by some users, I noticed you left for month. I'm guessing you felt hurt and attacked due to being severely judged and accused of things. But when you came back, it looked like you had not taken the advice seriously or made any changes in your behaviour. Let me tell you, from the best of my knowledge, why these people made such blunt statements about you. They are here to help. They have good intentions. They notice you have a restricting habit. They are giving you foresight on how to make your life easier with this math stuff. I mean, I don't agree with He-Mann's incredibly blunt delivery but I can tell he cares for your future. Why the hell would a random care about you? Let that sink in....

Don't feel bad or inferior or the like. We all have our strengths and weaknesses. Intelligence and math ability does not determine success in the future; it's hard work that does. Staying in your comfort zone and asking for help constantly won't do you any good.

So please. I want you to think rigorously about the advice you've received in this thread by multiple users. I believe it's excellent advice for anyone.

boredsatan · Oct 22, 2017

If there is a matrix
[2 0]
[0 -3]
and there is an equation y = 3x
then how would you describe the transformation and the inverse
Thanks

This question got deleted from this thread. Sorry about any trouble that I may have caused

kawaiipotato · Oct 22, 2017

boredsatan said:
If there is a matrix
[2 0]
[0 -3]
and there is an equation y = 3x
then how would you describe the transformation and the inverse
Thanks

This question got deleted from this thread. Sorry about any trouble that I may have caused

$\noindent Consider the vector $v = \begin{pmatrix}x\\y \end{pmatrix} = \begin{pmatrix}x\\3x\end{pmatrix}\in\mathbb{R}^2$ (just another way of representing that line $y=3x$. Plug in $x$ values to see this.). Then we apply the transformation to this vector by computing \\ $\begin{pmatrix}2&&0\\0&&-3\end{pmatrix}\begin{pmatrix}x\\3x\end{pmatrix} = \begin{pmatrix}2x\\-9x\end{pmatrix}.$\\ So $v_1 = 2x \\ v_2 = -9x$. So eliminating $x$, we get $v_2 = -\frac{9v_1}{2}$. \\ On the $v_1 - v_2$ plane, we get a straight line going through the origin with slope $-\frac{9}{2}$ under the transformation. \\ A similar way is done for the inverse transformation (you'd do the same thing except with the inverse matrix.).$

boredsatan · Oct 22, 2017

kawaiipotato said:
$\noindent Consider the vector $v = \begin{pmatrix}x\\y \end{pmatrix} = \begin{pmatrix}x\\3x\end{pmatrix}\in\mathbb{R}^2$ (just another way of representing that line $y=3x$. Plug in $x$ values to see this.). Then we apply the transformation to this vector by computing \\ $\begin{pmatrix}2&&0\\0&&-3\end{pmatrix}\begin{pmatrix}x\\3x\end{pmatrix} = \begin{pmatrix}2x\\-9x\end{pmatrix}.$\\ So $v_1 = 2x \\ v_2 = -9x$. So eliminating $x$, we get $v_2 = -\frac{9v_1}{2}$. \\ On the $v_1 - v_2$ plane, we get a straight line going through the origin with slope $-\frac{9}{2}$ under the transformation. \\ A similar way is done for the inverse transformation (you'd do the same thing except with the inverse matrix.).$

Thanks

boredsatan · Oct 22, 2017

Is the answer y' = (3^(x'/2))* - 3 ?

dan964 · Oct 22, 2017

boredsatan said:
Is the answer y' = (3^(x'/2))* - 3 ?

no, please pay attention to the answer given.
(I used (u,v) as opposed to v1 and v2)

The transformation turns a line from gradient y=3x into a line v=-9/2 u. More generally a line y=ax+b, into a line v=-1.5a*u +b

The inverse maps requires the inverse of the transformation matrix.

boredsatan · Oct 22, 2017

kawaiipotato said:
$\noindent Consider the vector $v = \begin{pmatrix}x\\y \end{pmatrix} = \begin{pmatrix}x\\3x\end{pmatrix}\in\mathbb{R}^2$ (just another way of representing that line $y=3x$. Plug in $x$ values to see this.). Then we apply the transformation to this vector by computing \\ $\begin{pmatrix}2&&0\\0&&-3\end{pmatrix}\begin{pmatrix}x\\3x\end{pmatrix} = \begin{pmatrix}2x\\-9x\end{pmatrix}.$\\ So $v_1 = 2x \\ v_2 = -9x$. So eliminating $x$, we get $v_2 = -\frac{9v_1}{2}$. \\ On the $v_1 - v_2$ plane, we get a straight line going through the origin with slope $-\frac{9}{2}$ under the transformation. \\ A similar way is done for the inverse transformation (you'd do the same thing except with the inverse matrix.).$

I don't really understand. Is it possible for you to explain it in simpler terms?

kawaiipotato · Oct 22, 2017

boredsatan said:
I don't really understand. Is it possible for you to explain it in simpler terms?

Which part don't you understand?

boredsatan · Oct 22, 2017

kawaiipotato said:
Which part don't you understand?

From the "so eliminating" part until the end of your answer

kawaiipotato · Oct 22, 2017

boredsatan said:
From the "so eliminating" part until the end of your answer

$$\noindent I simply solved the equations simultaneously. I.e. I solved $v_1 = 2x$ and $v_2 = -9x$ by ''eliminating'' $x$.$

boredsatan · Oct 22, 2017

Can you please explain how you would do it for the inverse?

kawaiipotato · Oct 23, 2017

VCE Maths questions help (2 Viewers)

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