anyone knows where to find the ans to A level chem our year ? ]]>

Moved your comment here as I believe you're referring to the **2009** H2 Maths P1 and not the 2008 one.

Errr ... for the relevant part of Q7(ii), the binomial expansion of (`a`+`b``x`^{2})^{−1} is as follows:

Since is the `b` in (1+`b`)^{n}, the next term would contain a `x`^{4} if we were to 'expand one more time' as follows:

From the above we can see that there is no `x`^{2} beyond the second term. I suspect that you've taken instead to be your `b` in (1+`b`)^{n}?

**stormangel:** This blog post was published on 12 Nov 2009 (two days after your H2 Paper 1) - very late *meh*?

for qn7ii, you need to expand (a+bx^2)^(-1) one more time as (1+b/a x^2) ^2 will have a term in x^2. ]]>

We let `d`_{1} be the direction vector of `l` i.e.

`d`_{1} =

We're given that (2, 3, 4) lies on `p`_{4}, and since we've proven that `l` lies on `p`_{4}

⇒ (0, 1, 0) lies on `p`_{4} too

⇒ we can form another direction vector `d`_{2} on the plane as follows:

`d`_{2} =

We can then cross `d`_{1} and `d`_{2} to obtain the normal of plane `p`_{4}:

`d`_{1} × `d`_{2}

=

So to get the cartesian equation of `p`_{4}:

`r`⋅

∴ `x` − `y` = −1, `z` ∈ ℝ

(yes **passerby** it's `z` ∈ ℝ, I've updated the solution 😉 )

Lastly, I would like to add that we can also show that line `l` lies in `p`_{3} through the following two expressions:

`x`+`z` = 0 ⇒ `x` = −`z`

`y`+`z` = 1 ⇒ `y` = 1−`z`

that's obtained using the RREF function in your GC when solving the equations of `p`_{1} & `p`_{2} in part (ii).

We can then sub the above expressions into the equation for `p`_{3} as follows:

LHS: 2(−`z`)+(1−`z`)+3`z`−1+`k`(`z`+2(1−`z`)+`z`−2) = 0 = RHS

∴ `l` lies in `p`_{3} for any constant `k`.

Anyway for those of you who are not yet aware, my H1 Maths Paper 1 and H2 Maths Paper 2 are now up.

I appreciate your discussions and comments here, and in response to some of the feedback, I've updated the diagrams in Q9 to more show more accurately that the bisector does indeed pass through the origin and `z`_{7}.

I don't think Little miss Loi covers JC chem so maybe u should try other websites. Its already out according to my tutor but i dun have the links >_< sorry...

Omg i rank highest in the chatter boxers <_<, just noticed... Well its constructive conv anyways (mostly) =P

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