Prelim 2016 Maths Help Thread (6 Viewers)

[leehuan]

See the 2U/3U syllabus or a textbook for the derivation

Emphasis on this. Still waiting for you to drop the stubborn attitude with textbooks @ eyeseeyou. It's insulting.

 

[eyeseeyou]

Emphasis on this. Still waiting for you to drop the stubborn attitude with textbooks @ eyeseeyou. It's insulting.

Well.....I've got notes with me atm and it doesn't have the derivation

 

[InteGrand]

Well.....I've got notes with me atm and it doesn't have the derivation

You could probably also find a derivation online with the help of a search engine.

 

[Trebla]

Well.....I've got notes with me atm and it doesn't have the derivation

What textbooks do you have?

Did you cover the derivation at school?

Did you look at the 2U/3U syllabus? There is actually a derivation in there.

 

[eyeseeyou]

What textbooks do you have?

Did you cover the derivation at school?

Did you look at the 2U/3U syllabus? There is actually a derivation in there.

old fitzpatrick

And PDF's of new fitzpatrick and Cambridge (don't have atm)

 

[eyeseeyou]

What textbooks do you have?

Did you cover the derivation at school?

Did you look at the 2U/3U syllabus? There is actually a derivation in there.

old fitzpatrick

And PDF's of new fitzpatrick and Cambridge (don't have atm)

 

[Paradoxica]

Well, EYESEEYOU, seeing as the sums to products and vice versa identities are not in the syllabus, you should not expect your notes to contain them.

Like I said, prove them yourself.

 

[eyeseeyou]

Well, EYESEEYOU, seeing as the sums to products and vice versa identities are not in the syllabus, you should not expect your notes to contain them.

Like I said, prove them yourself.

There was no need to capatalise my name in bold and enlargen it

 

[eyeseeyou]

Well, EYESEEYOU, seeing as the sums to products and vice versa identities are not in the syllabus, you should not expect your notes to contain them.

Like I said, prove them yourself.

There was no need to capatalise my name in bold and enlargen it

 

[Trebla]

old fitzpatrick

And PDF's of new fitzpatrick and Cambridge (don't have atm)

Did you look through those textbooks for a derivation?

 

[eyeseeyou]

Okay I am very confused with this:
1. Find the inverse function f^-1(x) of each function and verify that f^-1(f(x))=f(f^-1(x))=x
a. f(x)=(x-2)^2, x is less than or equal to 2
b. f(x)=x(x+2), x is greater than or equal to 1
c. f(x)=(x-1)^2+2, x is greater than or equal to 1

I can't seem to get this

 

[eyeseeyou]

Did you look through those textbooks for a derivation?

I only lookied at it for like 5 seconds b/c I didn't have the time to fully look at it

 

[leehuan]

I only lookied at it for like 5 seconds b/c I didn't have the time to fully look at it

Lol what

You have time to type questions up for BoS and wait but you merely glanced at the textbook examples?

 

[eyeseeyou]

Lol what

You have time to type questions up for BoS and wait but you merely glanced at the textbook examples?

I wasn't here for like the last day and a half (if you get what I mean)

 

[eyeseeyou]

DW leehuan, I'll look at it later

 

[leehuan]

I'll do the f(x)=x(x+2) bit (as in finding the inverse) though because that one might be a bit annoying unless you've seen how to apply the quadratic formula



f(x) has domain x≥1
So
f^-1(x) has range y≥1

 

[leehuan]

DW leehuan, I'll look at it later

You had better.

 

[eyeseeyou]

So I did this and am so confused:

f(x)=(x-1)^2+2,x≥1
y=(x-1)^2+2,x≥1
y-2=(x-1)^2,x≥1
x-2=(y-1)^2,y≥1
(y-1)^2=x-2,y≥1
y-1=√(x-2) ,y≥1
y=√(x-2)+1 ,y≥1

Could some1 tell me what I need to do next?

 

[leehuan]

So I did this and am so confused:

f(x)=(x-1)^2+2,x≥1
y=(x-1)^2+2,x≥1
y-2=(x-1)^2,x≥1
x-2=(y-1)^2,y≥1
(y-1)^2=x-2,y≥1
y-1=√(x-2) ,y≥1
y=√(x-2)+1 ,y≥1

Could some1 tell me what I need to do next?

The inverse function looks right but where you square rooted, you should put the ± sign in then drop it out the next step. At least, in my opinion.

You could potentially get away with it though because you continuously stated y≥1
_________

 

[eyeseeyou]

The inverse function looks right but where you square rooted, you should put the ± sign in then drop it out the next step. At least, in my opinion.

You could potentially get away with it though because you continuously stated y≥1
_________

I got y=1+ Squareroot of (x-2)

Is that the answer?