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Junior Cert 2011 : Maths Paper 2
Comments
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2 theorems in consecutive years has never happened so don't count on pythagoras to come up.
Anyone know how to do paper 1 Q 2 ( c ) ?
It was the one with the sets and there was one other question, it was express t in terms of s and r
for q2 c, (this is really hard to explain btw, so sorry if i make no sence
), but,
for part one, where you have to find the minimum value of #(PUQ)', it means you have to find the smallest possible number that would work in the part of the venn diagram outside of P and Q, to do this, you can assume that the 16 in P, and the 6 in Q and not part of the intersection, and that P and Q have nothing in the intersection, meaning that P + Q = 16 + 6, which is 22, meaning that the leftover 8 (30-22) would be #(PUQ)'.
for part two, you have to find the maximum value of #(PUQ)', meaning you have to find the largest possible number that would make sence in the part of the venn diagram outside of P and Q, and still add up to 30. To do this you can assume that the 6 in Q is also a part of P, meaning it would be in the intersection, meaning # P + Q = P (because Q is part of P) would be 16 only. This means that #(PUQ)' would be 30 - 16, which is 14.
Did that make sense?
for part three, you have to proove that u = p + x, x being the largest possible number outside of P and Q in the diagram, which mean you can assume its the same situation as in part (ii), where Q is also a part of P, this would mean that u = x - q + p + q, or, u = p + x
for the other question, t^2 - s = r, this is how you do it:
t^2 - s = r
t^2 = r + s (move s across the equal sign and change the sign)
t = (sqrt) r + s (find the square root of both sides, meaning that t^2 becomes t, and r + s becomes (sqrt) r + s
Hope I helped
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for q2 c, (this is really hard to explain btw, so sorry if i make no sence), but,
for part one, where you have to find the minimum value of #(PUQ)', it means you have to find the smallest possible number that would work in the part of the venn diagram outside of P and Q
This almost caught me out - in the frenzy of getting the paper, I missed the apostrophe, and answered the question differently, but I changed it soon afterwards :pac:0 -
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for q2 c, (this is really hard to explain btw, so sorry if i make no sence), but,
for part one, where you have to find the minimum value of #(PUQ)', it means you have to find the smallest possible number that would work in the part of the venn diagram outside of P and Q, to do this, you can assume that the 16 in P, and the 6 in Q and not part of the intersection, and that P and Q have nothing in the intersection, meaning that P + Q = 16 + 6, which is 22, meaning that the leftover 8 (30-22) would be #(PUQ)'.
for part two, you have to find the maximum value of #(PUQ)', meaning you have to find the largest possible number that would make sence in the part of the venn diagram outside of P and Q, and still add up to 30. To do this you can assume that the 6 in Q is also a part of P, meaning it would be in the intersection, meaning # P + Q = P (because Q is part of P) would be 16 only. This means that #(PUQ)' would be 30 - 16, which is 14.
Did that make sense?
for part three, you have to proove that u = p + x, x being the largest possible number outside of P and Q in the diagram, which mean you can assume its the same situation as in part (ii), where Q is also a part of P, this would mean that u = x - q + p + q, or, u = p + x
for the other question, t^2 - s = r, this is how you do it:
t^2 - s = r
t^2 = r + s (move s across the equal sign and change the sign)
t = (sqrt) r + s (find the square root of both sides, meaning that t^2 becomes t, and r + s becomes (sqrt) r + s
Hope I helped
Ahh thanks man, I can't believe I got the epxress T one wrong.
I think I got the rest right though, the only 1 I'm unsure was the tax one above the sets question
Was 2% levy, was that to find the 2% of 40,000?0 -
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Eh you all might think this is strange but i don't know what pythagorous's theorem is ? i thought it was like h squared + r squared = l squared or something like that ?
Quick description in MS Paint:
That's not how you prove the theory, but it should show you how to apply it in exam questions. I'll try and find the proof as it's a bit long and I can't really draw it up in Paint.0 -
Eh you all might think this is strange but i don't know what pythagorous's theorem is ? i thought it was like h squared + r squared = l squared or something like that ?
Quick summary of what Colm explained:
If you have a right angled triangle, and they tell you the two sides that make up the right angle, you can find out what the hypotenuse is(the side opposite to the right angle).
Say if it was 3 and 4, so
3^ + 4^ = hypotenuse^
9 + 16 = hypotenuse^
25 = hypotenuse^
sq.root of 25 = hypotenuse
5 = hypotenuse
^ means squared
They could come up in Paper 2 Q5, but the question might not be that direct, and I think it could come up in Q3 aswell0 -
Oh wow I'd love if Pythagoras somehow came up in a part C, so wonderfully easy
. They tend to save it for trigonometry though, sigh. Ummm the standard proof for good ole Pythag is....
OK, I just did a quick search online and the proof of the theorem is quite elusive, I know I found all the theorems and their proofs online one day, if I stumble across it I'll stick it up here. But anyway, I don't actually use the standard proof for Pythagoras, I found it really hard to remember, I use a method using a square...it's kinda hard to explain, but it's wonderfully easy and if anyone wants me to I'll try explain it. You're really unlikely to be asked on it though, sadly.0 -
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just want to make sure i got it right. 
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