The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

c3 functions

I was doing q6c on this paper and ran into a misunderstanding :s-smilie:

QP: https://07a69ccf283966549a9350d1a66951a7bc96e2dc.googledrive.com/host/0B1ZiqBksUHNYZ0JQM1NRcmdHdXM/June%202014%20(R)%20MA%20-%20C3%20Edexcel.pdf

surely we square and cube everything inside the bracket of the g(x) function? (as shown in the image i uploaded)


can someone explain why this is wrong, the x value in the g(x) function is 2x so surely we square and cube that?





@Zacken
(edited 7 years ago)
c3gx.png3.4KB
Reply 1
Avatar for Zacken
Zacken
22
Original post by Katiee224


No, the x value is x. That's all you're changing.

If it helps, you could write it as g(x) = ln 2 + ln x.

So g(x^2) = ln 2 + ln x^2 = ln (2x^2).
Reply 2
Avatar for Katiee224
Katiee224
OP
11
Original post by Zacken
No, the x value is x. That's all you're changing.

If it helps, you could write it as g(x) = ln 2 + ln x.

So g(x^2) = ln 2 + ln x^2 = ln (2x^2).


2 minute wait for a reply zacken, you're slacking :tongue:


ah ok I see now, what if we had '2y' in the bracket, so

g(x) = ln(2y)

and wanted to work out g(x^2)?

or is that not possible as it has to be a function of x? :colondollar:
Reply 3
Avatar for Zacken
Zacken
22
Original post by Katiee224
2 minute wait for a reply zacken, you're slacking :tongue:


ah ok I see now, what if we had '2y' in the bracket, so

g(x) = ln(2y)

and wanted to work out g(x^2)?

or is that not possible as it has to be a function of x? :colondollar:


Well, yeah. Then y is basically just a constant instead of a variable, so g(x) = g(x^2) = g(x^elephant) = ln(2y).

(basically what you said about it having to be a function of x)
Reply 4
Avatar for Katiee224
Katiee224
OP
11
Original post by Zacken
Well, yeah. Then y is basically just a constant instead of a variable, so g(x) = g(x^2) = g(x^elephant) = ln(2y).

(basically what you said about it having to be a function of x)



hahaha okay thanks for the help:tongue:, btw do you recommend doing TeeEm's papers for c3/c4 revision or get the edexcel past papers done first? :colone:

how have you been revising for these subjects? :smile:
Reply 5
Avatar for Zacken
Zacken
22
Original post by Katiee224
hahaha okay thanks for the help:tongue:, btw do you recommend doing TeeEm's papers for c3/c4 revision or get the edexcel past papers done first? :colone:

how have you been revising for these subjects? :smile:


Get the Edexcel papers done first.

I did them in Jan. :smile:
Reply 6
Avatar for Katiee224
Katiee224
OP
11
Original post by Zacken
Get the Edexcel papers done first.

I did them in Jan. :smile:


haha you cocky lil :laugh:

did you get 100 UMS in all of them I'm guessing?:tongue:
Reply 7
Avatar for Zacken
Zacken
22
Original post by Katiee224
haha you cocky lil :laugh:

did you get 100 UMS in all of them I'm guessing?:tongue:


Something like that. :tongue:

I'm sure you'll do fine! :biggrin:
Reply 8
Avatar for Katiee224
Katiee224
OP
11
Original post by Zacken
Something like that. :tongue:

I'm sure you'll do fine! :biggrin:


Gotta let me know your maths results when you get them, so I can stare at your UMS in envy :colone:
Reply 9
Avatar for Zacken
Zacken
22
Original post by Katiee224
Gotta let me know your maths results when you get them, so I can stare at your UMS in envy :colone:


It's nothing special. :lol: UMS sucks anyway. :tongue:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you