Official BOS Mathematics Seminar: "How to solve problems." (5 Viewers)

[justem]

I expected only 3. Fawun, rumbleroar and you

True

 

[anomalousdecay]

I was surprised that most of you looked normal-ish.

The first thing you said to me

 

[Fizzy_Cyst]

Like did you expect us to look alien? Hehe

I expected everyone to look really nerdy, LoL.

The first thing you said to me

Bwahahahahaha!

My social skills really shone through!

 

[enoilgam]

I expected everyone to look really nerdy, LoL.

I kind of expected this as well when I first showed up to a meat ages ago - to be honest, the biggest BoS myth is that we are all basements.

 

[dunjaaa]

Thanks for a very informative seminar carrot, you should host more in the future!

 

[Zeref]

So I'm doing some more research about yesterdays seminar:

"If you eat a whole pint of ice cream, then you won't be hungry."

Converse: If you aren't hungry, then you have eaten a pint of ice cream
Inverse: If you haven't eaten a pint of ice cream, then you are hungry
Contra positive: If you are hungry, then you have not eaten a whole pint of ice cream.

Does contra positive mean iff?
Holy crap it's so mindfck.

 

[enoilgam]

So I'm doing some more research about yesterdays seminar:

"If you eat a whole pint of ice cream, then you won't be hungry."

Converse: If you aren't hungry, then you have eaten a pint of ice cream
Inverse: If you haven't eaten a pint of ice cream, then you are hungry
Contra positive: If you are hungry, then you have not eaten a whole pint of ice cream.

Does contra positive mean iff?
Holy crap it's so mindfck.

It's disappointing that they dont teach this stuff in school - we were taught it in uni for philsophy (which is compulsory for all degrees at ND).

 

[Fizzy_Cyst]

Remember if A then B


Seems like contra positive is saying

If not B then not A

 

[justem]

Remember if A then B


Seems like contra positive is saying

If not B then not A

I really wanted to ask you this, why don't you have an icon picture???

 

[Fizzy_Cyst]

I really wanted to ask you this, why don't you have an icon picture???

I do.

But, it only displays when it is not being observed.

Observation collapses the wave function of the .jpeg

 

[Carrotsticks]

So I'm doing some more research about yesterdays seminar:

"If you eat a whole pint of ice cream, then you won't be hungry."

Converse: If you aren't hungry, then you have eaten a pint of ice cream
Inverse: If you haven't eaten a pint of ice cream, then you are hungry
Contra positive: If you are hungry, then you have not eaten a whole pint of ice cream.

Does contra positive mean iff?
Holy crap it's so mindfck.

Contra positive doesn't mean iff.

Say my conditional statement is P --> Q

Contrapositive is NOT Q --> NOT P.

IFF is P --> Q AND Q --> P

Good to see that you're exploring beyond what I went through in the seminar!

 

[Zeref]

Contra positive doesn't mean iff.

Say my conditional statement is P --> Q

Contrapositive is NOT Q --> NOT P.

IFF is P --> Q AND Q --> P

Good to see that you're exploring beyond what I went through in the seminar!

Ahhhh, so using your example (just so I can get the hang of it) :

"If I eat too much junk food, I will be unhealthy"

Converse:If I am unhealthy, it is because I ate junk food
Inverse: If I don't eat much junk food, I will be healthy
Contra positive: If I am healthy, it is because I didn't eat junk food

so that makes IFF converse?
Which of the three is most commonly used for maths questions?

 

[Carrotsticks]

Ahhhh, so using your example (just so I can get the hang of it) :

"If I eat too much junk food, I will be unhealthy"

Converse:If I am unhealthy, it is because I ate junk food
Inverse: If I don't eat much junk food, I will be healthy
Contra positive: If I am healthy, it is because I didn't eat junk food

so that makes IFF converse?
Which of the three is most commonly used for maths questions?

Yep, those are correct.

I don't quite get what you mean when you ask 'So that makes iff converse', can you clarify?

Also, in HSC Mathematics problems, it is usually the original conditional statement that you'll need an understanding of. Maybe a bit of the biconditional statement too, which I've seen appear in problems.

HOWEVER, I am not 100% sure if the biconditional problems are there because the teacher intended for students to prove both directions (or proving one direction only using the 'snowplough'), or because it's just there to sound fancy without the realisation of what it means.

The reason why I addressed this is because in my experience of marking and observing students (and some teachers too!), I've noticed that a lot of them seem to assume that A --> B automatically implies that B --> A. In other words, they assume that the condition is biconditional when in fact it isn't.

For example, f''(A) = 0 is a necessary, but not a sufficient condition for a point of inflexion. A common misconception is that f''(A) implies a point of inflexion at x=A.

Another common mistake is if the question says "Prove that if A, then B" and students go ahead and prove that if B, then A instead.

 

[Zeref]

I don't quite get what you mean when you ask 'So that makes iff converse', can you clarify?

nvm i derped for a moment xD

So in a sense inverse and contra positive aren't needed right?