Silly Questions Thread

[Aqualim]

ok because the formula in the answers says which is the same as your answer.

But where did you pull the 1056 from?

[GerrySly]

ok because the formula in the answers says which is the same as your answer.

But where did you pull the 1056 from?

"Decreasing at 12% per year"

[Aqualim]

ok so I'm having trouble with solving simultaneous equations which have more than 2 variables.
Heres the question;
Find the values of a, b and c;







I've seen ways for solving simultaneous equations on google, but they only show worked examples for when all three variables are separated after expansion, whereas if you expand this equation you will have two variables placed together

[the.watchman]

[1] - [2]: [4]

[2] - [3]:





[5]

[5] -> [4]:

BLAH BLAH BLAH



sub both into one of the eqns to get c

[Aqualim]

Thanks for that but when you took [2] from [3] what happened to the ''a's''? did you just eliminate them because we only want to find out b?

[the.watchman]

Thanks for that but when you took [2] from [3] what happened to the ''a's''? did you just eliminate them because we only want to find out b?

No, I divided both sides by a

[ioaus09]

lol, got another question: Can someone explain this - f:B --> Z is defined by f(n) = 1 - n^2 then which one or more of the following is/are true?

A) f is a one-to-one function
B) f is an onto function
C) f is a function, but is neither one-to-one nor onto
D) f is not a function

There can be more than one answer

[m@tty]

So, ?

What are and ?

[brightsky]

Assuming that means integer, then I think the answer would be D). The graph would be discontinuous.

[m@tty]

Oh yeah, that seems plausible. Do they have questions like that in Methods? Where the co-domain is restricted to integers or natural sets?

If that does represent integers then the answer would indeed be D, as brightsky pointed out.

[/0]

Not a very methodsy question.

A function is a set of ordered pairs from with the property that for every there is exactly one such that .

If we assume Z is the integers and B can be anything, then I don't think any of the statements are true for all B.
See, if we have then is not a function, but if we have , then we can choose so that is a function.

By the way, if contains a continuous interval in , then the answer must be D), as brightsky said.

[Aqualim]

Just wondering what would be the quickest method when sketching a graph, with the equation as follows;



Also was given an exponential modelling equation (can't post up due it being on a test) which stated there was a cooling temperature of something like 40 degrees and an initial temperature of 70 degrees, and normally the initial temperature is placed within the equation where it says; , but instead the cooling temperature was placed inside the equation whilst the initial temperature replaced the y value. How is this possible? unless it was a mistake made by the teachers? 

[the.watchman]

I'd say, for now, split up the function into a hybrid, then sketch the individual parts
But once you get some idea for what to do, you should notice that there is an axis of symmetry when (if |f(x)|), f(x)=0 and the 'positive' side is reflected to make up the 'negative' side

[m@tty]

Yeah, for your equation notice that every x is always positive, so all you have to do is sketch for and reflect in the y axis..

[Aqualim]

ok so would it split up like so?