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Need help with explaining how to express an equation in polynomial form.

Howdy :smile:.

I'm going through some past exam style questions and I can't understand how to fully do this question. Here is the question and the answer format fuck.JPG

Could someone explain what is going on for each line please? I have crudely labelled each line as to make it easier to explain, rather than typing each section out. There are not other questions in this format so I have nothing else to compare it to, to help me.





(edited 10 years ago)
format fuck.JPG38.5KB
Reply 1
Avatar for nerak99
nerak99
13
The first equation tells you (in a slightly convoluted way) what f(x) is. This means that you can substitute the polynomial form of this f(x) for the f(x) in (1) and the rest is algebra really.

Does that help?
Reply 2
Avatar for james22
james22
16
What is f(x)?
Reply 3
Avatar for jojo55
jojo55
OP
11
Original post by james22
What is f(x)?


Sorry, I have put it on the image posted in the initial post.
Reply 4
Avatar for jojo55
jojo55
OP
11
Original post by nerak99
The first equation tells you (in a slightly convoluted way) what f(x) is. This means that you can substitute the polynomial form of this f(x) for the f(x) in (1) and the rest is algebra really.

Does that help?



I forgot to put f(x) into the image that I posted. It is in there now. I can see parts of where f(x) goes into but I can't clearly understand how each line is done, as if I was going to do this again if a question came up, like this, in my exam.
Reply 5
Avatar for james22
james22
16
1. and 2. are just replacing x with f(x) then f(x) with its definition.

3. Is just expanding the brackets.

4. Is just multiplying everything in the bracket by 1/4.

5. is just collecting like terms.
Reply 6
Avatar for jojo55
jojo55
OP
11
Original post by james22
1. and 2. are just replacing x with f(x) then f(x) with its definition.

3. Is just expanding the brackets.

4. Is just multiplying everything in the bracket by 1/4.

5. is just collecting like terms.



Thanks a lot :smile:. I just found out I was not expanding the brackets correctly and I didn't understand that 336/64 is the same as 21/4, and that it was changed to be able to simplify properly.

I think I've been studying too much as those were silly mistakes. Time for a break.

Thanks again for taking the time to help me x x

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