Check my working

[kenhung123]

Can someone check if my working is valid in exam 2?

When I solve for x and get a few answers, instead of OR can I say x=3, 12, 15?

When I work with pdf's, can I find mean, median and mode in terms of f(x)? E.g. Instead of finding median by can I do
In this case it won't make a difference but for cases when the function is very long and tedious to write the whole thing.  out

Also when we sub in points (x) for whatever reason, do we need to show that step or we can say "when x=1, f(1)=blah" Or we need to show when x=1 f(1)=1^2=1

Is there any type of notation to represent gradient of a normal? Perhaps ?

[the.watchman]

1) Yes

2) If you write f(x), you should go from to m, because f(x) is from to with 0 otherwise

However, if you want to use 0 to m, then I would write out the function

3) I don't think it matters, but sometimes I write it out to make sure it stays clear

4) I write "Grad. of normal"

[kenhung123]

Oh actually that makes sense! Wow, step 2 is totally wrong and I didn't realise!

Thanks for that

[kenhung123]

Also, do you lose marks for not leaving your answer in simplest form (perhaps forgetting to cancel common factors in numerator and denominator)

[vea]

Also, do you lose marks for not leaving your answer in simplest form (perhaps forgetting to cancel common factors in numerator and denominator)

It depends how much marks the question is worth but I think you should always have it in simplest form anyway. If you're talking about this in exam 2, you could always put the fraction in the calculator to see if it simplifies down any further.

[Souljette_93]

Is there any type of notation to represent gradient of a normal? Perhaps ?

I use _n and _t when specifying the gradient.

also, do you lose marks for not leaving your answer in simplest form (perhaps forgetting to cancel common factors in numerator and denominator)

For Exam 1, yes you do, if the mark is worth more than 1. Exam 2, i assume you should leave it Simplest, since they know you can use a calculator.

regards,
Souljette

[the.watchman]

Is there any type of notation to represent gradient of a normal? Perhaps ?

I use _n and _t when specifying the gradient.

Not bad, but a little dangerous, unless you actually define what they are

[Souljette_93]

Not bad, but a little dangerous, unless you actually define what they are

 Really how come? I always do it like this, i think i saw it in a book or something. Can it mean anything else?

regards,
souljette

[the.watchman]

It's not too bad as I said, but I always like to define everything

[m@tty]

I use(d) and .

Also, you don't need to say "at x=1, f(1)= ... "
If the function is given by f(x), then f(1) already means, the value of the function f at x=1.

With integrating f(x) instead of writing out the entire expression, it is mathematically correct, but it seems a bit of a cop out. How long does it take to write out an expression?

[akira88]

I use(d) and .

Also, you don't need to say "at x=1, f(1)= ... "
If the function is given by f(x), then f(1) already means, the value of the function f at x=1.

With integrating f(x) instead of writing out the entire expression, it is mathematically correct, but it seems a bit of a cop out. How long does it take to write out an expression?

This is what I do too

[kenhung123]

When I am asked to find the domain are these 2 ways of stating in correct?:
and

I'm not entirely sure if I need the epsilon..

[|ll|lll|]

When I am asked to find the domain are these 2 ways of stating in correct?:
and

I'm not entirely sure if I need the epsilon..

Yes it's correct. But I suppose you need the epsilon since you have 'x is an element of'

[moekamo]

When I am asked to find the domain are these 2 ways of stating in correct?:
and

I'm not entirely sure if I need the epsilon..

no you dont need an epsilon, you need an:

Code: [Select]

[tex] \in [/tex]

[kenhung123]

Oh ok. Thanks