Questions thread

[Ilovemathsmeth]

I think they want you to find the value(s) of x for which

Preferentially use a graphics calculator for this question.

By hand:







From this, the x-intercepts occur when x = 0 and when:

which gives x = 1. Thus by sketching the graph from here carefully, it is possible to determine when the graph of

[kenhung123]

Oh ok thanks. I firstly got V=x(36-2x)(20-2x) without simplification (I didn't know the method of factorising brackets) Is this considered wrong?

[Ilovemathsmeth]

That's not wrong either, you just need to remove the common factor of 2 in each bracket:

[Hielly]

Hey im a bit confused with dilation.
State a transformation which maps the graphs of y = f (x) to y = f1(x) for each of the
following:
a)
i) f (x) =1/x^2
ii) f1(x) =5/x^2

[/0]

The original graph is



The image is



so



Dilation by factor 5 from the x-axis

[Hielly]

The original graph is



The image is

hey thanks, i dont understand the second bit y'/5=1/x^2

[Ilovemathsmeth]

That is so that you get the dilations in one place for the next step;







This indicates a dilation of factor 5 from the x-axis.

[Hielly]

is y'=2|x| same as y'=|2x| ?

[Ilovemathsmeth]

The same.

[Hielly]

okay thanks!
Also how do you know that y=1/(x^3/4) is neither odd or even

I know that f(-x)=-f(x) indicates odd and  f(-x)=f(x). Not sure how to find out if an equation is neither odd or even

Thanks

[TrueTears]

okay thanks!
Also how do you know that y=1/(x^3/4) is neither odd or even

I know that f(-x)=-f(x) indicates odd and  f(-x)=f(x). Not sure how to find out if an equation is neither odd or even

Thanks

If it doesn't satisfy both conditions then its neither.

[Hielly]

could you elaborate more by explaining why this y=1/(x^3/4) is neither?

Thanks

[TrueTears]

Just make sure it doesn't satisfy both conditions.



Try



Undefined.

Thus both conditions are undefined.

So it's neither.

[Hielly]

Hey, im confused about the dilation, im not sure if it is dilation in the x-axis or the y-axis. Could someone explain 1a and 1c

thanks

[Ilovemathsmeth]

1. a) This one can be done by inspection (fastest, but not advised for a complex function). It appears as though it is in the form which suggests a dilation of factor k from the x-axis. form. Thus a dilation of factor 2 from the x-axis.

1. c) Also can be done by inspection; same reasoning as above, this should be a dilation of factor 4 from the x-axis.

Theoretically, suggests a dilation of factor k from the x-axis as it affects the y-values, i.e. it stretches/compresses the y-values by that factor of k. Thus a dilation from the x-axis is the same as a dilation parallel to the y-axis as both affect the y-values or f(x).