Silly Questions Thread

[Aqualim]

When dealing with questions relating to solving sin or cos, must we memorise the exact values table/triangle or will we get given it on the formula sheet when in the exam?

[cipherpol]

Not on the formula sheet, so yeh, remember it

[the.watchman]

You should be able to remember it, but it can be in your bound notes (don't waste space on it if you can avoid it though)

[kyzoo]

Trust me, at the end of the year this stuff will be so ingrained into you that you won't need a reference to recall it. It's the same thing with the quotient rule, at first it's daunting, but in the end it's automatic knowledge.

[the.watchman]

Trust me, at the end of the year this stuff will be so ingrained into you that you won't need a reference to recall it. It's the same thing with the quotient rule, at first it's daunting, but in the end it's automatic knowledge.

+1 Very true! I'd say just sit down for 90 seconds and memorise them (look for patterns), then you'll know them for life

[Blakhitman]

Didn't want to start a new thread, and I think this is a silly question!

Ok, I've attached a worked example from my textbook concerning the product rule, what I want to know is why on the third step, the becomes

It's probably obvious, but I haven't seen it.

[brightsky]

They took out the factor .




Let and



Taking out the factor



Substitute in back the values for and :

which is your third step.

[stonecold]

damn your quick brightsky

yepp, i was gonna say that.  learnt that just yesterday.  it is fair confusing at first.

[Blakhitman]

oh man, seriously thanks heaps brightsky!

And Stonecold, it's the intention that counts :p

[Ilovemathsmeth]

Aqualim, you have to memorise the exact values or if you prefer, memorise their derivation. Like Kyzoo said, this stuff will become ingrained by the end of the year. Sure for exam 2, you can put them in your bound notes but you're almost guaranteed a circular functions question on exam 1, that relies on your knowledge of exact values. It isn't provided on the reference sheet.

[Aqualim]

a Mobile telephone company in a small country has only two plans for monthly payment;
Plan A: a Fixed charge of $30 and 50 cents a call after 150 calls. There is no extra charge for the first 150 calls
Plan B: No fixed charge and 30 cents a call

b) the rule for the cost of plan A, of 'n' calls is;


Given that 'c' is when n is equal to or lower than 150, and that 'an+b' is when 'n' is greater than 150

Hence, sketch the graph of Plan A.

When I sketch this graph I found that the gap between the first part of the hybrid and the second, didn't match the question. It looked like something below;

Shouldn't the hybrid graph be joined, as it won't cost an extra 60 odd dollars after the 150 calls.

[Stroodle]

What was your value for b?

[Aqualim]

[Stroodle]

The second part of the hybrid function should be C=0.50n-45 where n is greater than 150.


Edit* there's different ways to get this. I prefer to do it by solving the equations 30=150x+y and 31=152x+y

[Aqualim]

The second part of the hybrid function should be C=0.50n-45 where n is greater than 150.


Edit* there's different ways to get this. I prefer to do it by solving the equations 30=150x+y and 31=152x+y

Ok you've lost me, wouldn't you expect the +b to just be the fixed charge?