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Level 2 Further Maths - Post some hard questions (Includes unofficial practice paper)

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Reply 140
Original post by B0redBrioche
Okay i've got x^3-3x^2y-3xy^2-y^3 but I don't know how to simplify it further and I know you probably can

When simplifying you want to try to avoid expanding as much as possible or you may get something like this and then get stuck.

There's a few ways to approach this question. One way is to use "difference of two squares" on the numerator.
Original post by notnek

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Original post by notnek
Simplify:

(x2xy)2(xyy2)2(x+y)\displaystyle \frac{(x^2-xy)^2-(xy-y^2)^2}{(x+y)}


Would it be (x-y)^3(x+y) ?
Reply 143
Original post by notnek
Simplify:

(x2xy)2(xyy2)2(x+y)\displaystyle \frac{(x^2-xy)^2-(xy-y^2)^2}{(x+y)}


(x-y)^3.

This is really useful BTW! :smile:

p.s. is your previous matrices question on the spec? never seen anything like it! i somehow managed to get both theta and alpha as -1 xD
Reply 144
Original post by _gcx

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Nice solution. It sounds like you're not doing Further Maths - is that right? I'm sure you would have done well in it.
Reply 145
Here's a type of question that I've seen a few times in papers but it's often not done well by students:

A function ff is defined by f(x)=x23x4f(x)=x^2-3x-4 and 2x6-2\leq x \leq 6.

Find the range of f(x)f(x).


EDIT : Now I'm getting confused and wondering if I have seen this type of question in Level 2 FM. But it's worth trying anyway.
(edited 6 years ago)
Reply 146
Original post by chinkinator
(x-y)^3.

This is really useful BTW! :smile:

p.s. is your previous matrices question on the spec? never seen anything like it! i somehow managed to get both theta and alpha as -1 xD

It's too hard to be a question in the exam (probably) but it can be done with Level 2 FM knowledge/methods, as I showed in the solution.
Original post by notnek
Here's a type of question that I've seen a few times in papers but it's often not done well by students:

A function ff is defined by f(x)=x23x4f(x)=x^2-3x-4 and 2x6-2\leq x \leq 6.

Find the range of f(x)f(x).


Spoiler

(edited 6 years ago)
Reply 148
Original post by notnek
Here's a type of question that I've seen a few times in papers but it's often not done well by students:

A function ff is defined by f(x)=x23x4f(x)=x^2-3x-4 and 2x6-2\leq x \leq 6.

Find the range of f(x)f(x).


-16<f(x)<14? (< or equal to)
Original post by notnek
Here's a type of question that I've seen a few times in papers but it's often not done well by students:

A function ff is defined by f(x)=x23x4f(x)=x^2-3x-4 and 2x6-2\leq x \leq 6.

Find the range of f(x)f(x).


EDIT : Now I'm getting confused and wondering if I have seen this type of question in Level 2 FM. But it's worth trying anyway.


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Original post by TheMightyBadger

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I got the same.
Reply 151
@TheMightyBadger is correct. Unfortunately not correct @chinkinator @B0redBrioche- think about the shape of a quadratic graph and how you would work out its range.
Original post by notnek
@TheMightyBadger is correct. Unfortunately not correct @chinkinator @B0redBrioche- think about the shape of a quadratic graph and how you would work out its range.


Ahh yes i get it now, find the minimum turning point for the lowest bound of the range (1.5) instead of substituting -2. An easy mistake to make!
Latex-ed my questions:

1.Prove tan2θ+cos2θ=tan2θsin2θ+1 \tan ^2 \theta + \cos ^2 \theta = \tan ^2 \theta \sin ^2 \theta + 1

2. Let f(x)=1x f(x)=\sqrt{\frac{-1}{x}}
a. Find a suitable domain for ff
b. Find the range of ff
Original post by etothepiiplusone
Latex-ed my questions:

1.Prove tan2θ+cos2θ=tan2θsin2θ+1 \tan ^2 \theta + \cos ^2 \theta = \tan ^2 \theta \sin ^2 \theta + 1

2. Let f(x)=1x f(x)=\sqrt{\frac{-1}{x}}
a. Find a suitable domain for ff
b. Find the range of ff


I will try number 1 later because it requires more thought, but for number 2:

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Reply 155
Original post by etothepiiplusone
Latex-ed my questions:

1.Prove tan2θ+cos2θ=tan2θsin2θ+1 \tan ^2 \theta + \cos ^2 \theta = \tan ^2 \theta \sin ^2 \theta + 1

2. Let f(x)=1x f(x)=\sqrt{\frac{-1}{x}}
a. Find a suitable domain for ff
b. Find the range of ff


domain: x<0
range: 0<fx<infinity
Reply 156
Probably the last one from me today. If I have free days then I'll try to post more questions before Paper 2. I wish everyone luck in their exam tomorrow :smile:



The diagram shows a circle which touches the yy-axis and has a centre at the point (a,0)(a, 0) where aa is a positive constant.

Given that the point (4,3)(4, -3) lies on the circle, find the value of aa.
Original post by chinkinator
domain: x<0
range: 0<fx<infinity


< infinity is a bit unnecessary, but yes
Original post by notnek
Probably the last one from me today. If I have free days then I'll try to post more questions before Paper 2. I wish everyone luck in their exam tomorrow :smile:



The diagram shows a circle which touches the yy-axis and has a centre at the point (a,0)(a, 0) where aa is a positive constant.

Given that the point (4,3)(4, -3) lies on the circle, find the value of aa.


Spoiler

Original post by notnek
Probably the last one from me today. If I have free days then I'll try to post more questions before Paper 2. I wish everyone luck in their exam tomorrow :smile:



The diagram shows a circle which touches the yy-axis and has a centre at the point (a,0)(a, 0) where aa is a positive constant.

Given that the point (4,3)(4, -3) lies on the circle, find the value of aa.


Spoiler

(edited 6 years ago)

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