Edexcel FP1 Thread - 20th May, 2016

I think simultaneous equations w/ matricies will come up - never seen it before and i have no idea how to do them lol

I think simultaneous equations w/ matricies will come up - never seen it before and i have no idea how to do them lol

Do you mean using simultaneous equations to solve matrices? I don't think that's on spec (although it was in my GCSE).

chapter 4 ex 4j and point 4.11 example 24

seems easy enough just want to confirm the order of each element within the matrix

Don't have a textbook, but:

If you have the simultaneous equations:

$ax+by = c$

and

$dx + ey = f$

Then you write down:

$\displaystyle \begin{pmatrix}a &b \\ d & e\end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix}c \\ f \end{pmatrix}$

yh i'm just getting that - tbh i would just use my graphical to solve it for me and then i know which values to get lol

Look at my edited post, it's not hard to understand why that works.

Is it part a or b you're struggling with?

I was thinking that! and me neither lmaoo

For the proof of divisibility qs- I always use the following method- can someone pls check for me if it is the right way to do it/would get me full marks:

E.g. prove that f(n)=7^(2n)-48n-1 is divisible by 2304
sub in 1, make assumption n=k etc... then

f(k+1)-f(k)= 7^(2k+2) - 48(k+1) -1 - 7^(2k) +48k + 1
= 48(7^(2k)) - 48

then I rearrange f(k) to make 7^(2k) subject of the equation
i.e. 7^(2k)= f(k) + 48k + 1
Then sub it in to f(k+1)-f(k)

Is this a correct way of doing it??

For the proof of divisibility qs- I always use the following method- can someone pls check for me if it is the right way to do it/would get me full marks:

E.g. prove that f(n)=7^(2n)-48n-1 is divisible by 2304
sub in 1, make assumption n=k etc... then

f(k+1)-f(k)= 7^(2k+2) - 48(k+1) -1 - 7^(2k) +48k + 1
= 48(7^(2k)) - 48

then I rearrange f(k) to make 7^(2k) subject of the equation
i.e. 7^(2k)= f(k) + 48k + 1
Then sub it in to f(k+1)-f(k)

Is this a correct way of doing it??

For divisibility tests, is the conclusion different from true for n=k, k+1,n =1, so all n. Do you have to state since f(k) divisible by n, so f(k+1) is divisible by n etc.

If this is when n is more than or equal to 2 - you need to sub in 2 as someone pointed out on the forum. Then do the simple induction process - finally on to your conclusion. Done.

Yes.