VCE Methods Question Thread!

[kinslayer]

1)



f(0) = 0 implies that c = 0, and f'(0) = -1 implies that b = -1. So:

.

But f(4) = 0, so a = 4/16 = 1/4. Therefore:

.

2)



So:

[Reus]

If I have h(x) defined as something on a ti-nspire cx cas how can I undefine it without deleting the whole document?

make a new document?

[Zealous]

If I have h(x) defined as something on a ti-nspire cx cas how can I undefine it without deleting the whole document?

So if you have defined h(x), you can delete the defined function with:



("h" should show up in bold to show you've defined it)

This is also accessible through Menu -> [1] Actions -> [3] Delete Variable.

[paper-back]

2) Find the derivative of y=

Thanks!

You can also use the chain rule and quotient rule in combination to find the derivative

[Jason12]

if a question asks for an answer to 1 decimal point and i have the answer has 3.397 is the correct answer 3.4 or 3.5? One VCAA solution rounded it to 3.5 so I presume that is the correct way?

[lzxnl]

Seriously? Perhaps there's an error in your working somewhere. I highly doubt VCAA would round like that.

[Reus]

Differentiate with respect to x:
2x²+6x+5 / x²+2x+1



Got a slightly different answer to what it had in the back of the book... Not too sure where I went wrong either.

[b^3]

Just depends how they simplified it at the end.

[Reus]

Just depends how they simplified it at the end.

Thanks for that! One more inquiry, differentiate sin(x)/√x
I ended up with the same answer as the book however I have a 4 in front of the √x as my final solution, whereas they have a 2? :/

I have:
2x cos x–sin x/ 4 √x³

they have:
2x cos x–sin x/ 2 √x³ 

[b^3]

[melons]

When you identify a stationary point as a stationary point of inflection (through a gradient sign test or otherwise), do you need to state whether it is positive or negative?

[Einstein]

when defining functions - writing function notation, why is the co-domain (range?) usually R, and not the actual range for example R/{0} etc.

In my textbook it says - Y is not necerssarily the range but it is a set that contains the range, called the co - domain..... ran f = [0,6], but is usually R.

Thanks

[lzxnl]

when defining functions - writing function notation, why is the co-domain (range?) usually R, and not the actual range for example R/{0} etc.

In my textbook it says - Y is not necerssarily the range but it is a set that contains the range, called the co - domain..... ran f = [0,6], but is usually R.

Thanks

The codomain is just the set that the function maps onto. It's easier to write a function maps to R as opposed to R\{0}

[Einstein]

The codomain is just the set that the function maps onto. It's easier to write a function maps to R as opposed to R\{0}

so when we write in function notation is it always -> R, f(x)...?

also with this question (attachment) , when you graph it the x int is -2, so shouldn't the domain be [-2,infinity)? i know it does say x is an element of any positive real number, can you explain this in this context?

thanks

[IndefatigableLover]

also with this question (attachment) , when you graph it the x int is -2, so shouldn't the domain be [-2,infinity)? i know it does say x is an element of any positive real number, can you explain this in this context?

thanks

Basically your domain is all positive numbers excluding zero. In this case you are excluding all negative values of 'x'. Although the domain normally for your function is 'R', it wouldn't be since you have negative values of 'x' whilst your domain only specifies for positive values. You don't have to worry about the 'x' intercept in this case.

If you were to graph this then you'd just draw from but make sure when you label your endpoint for x=0 that it is a hollow circle and not a coloured in one since it does not include the value of zero since it's all positive real numbers (someone correct me if I'm wrong on this point).