2024 Ext2 HSC Solutions to Q10 and Q16bii (1 Viewer)

[epicmaths]

These took a while to write out - I wonder how they will mark 16bii), the justify definitely deserves 1 mark beyond just recognising a pattern.

My preferred way to answer this question is using modulo 18,
NESA's likely preference is mathematical induction.

Either way this is a demanding mark to achieve if they commit to marking the justification properly.

 

[jonolad69]

q10 doesnt seem right, may want to double check ur solutions

also q17

 

[SMARTYPANTS_SINGH]

q10 doesnt seem right, may want to double check ur solutions

also q17

For 10 the working out or the answer doesn’t seem right? Cause everyone I’ve talked to said it’s D

 

[jonolad69]

For 10 the working out or the answer doesn’t seem right? Cause everyone I’ve talked to said it’s D

the answer is B

 

[jonolad69]

why does everything think its D? i dont get it.

if u do ur h/w u can clearly see its D

 

[kendricklamarlover101]

the way i did bii) was proving that

using sum to product formula surely i get the full marks right

 

[epicmaths]

the way i did bii) was proving that

using sum to product formula surely i get the full marks right

Oooh that's lit, I'm sure that would do it and funnily enough sum to product also produces a divisibility by 18 argument.

 

[tywebb]

here solution to q10 utilising am-qm inequality

it can be done using calculus too but the am-qm inequality more efficient

most people heard of the am-gm inequality, but the am-qm often helps if u want the inequality to go "the other way"

 

[tywebb]

there has been the accusation that the am-qm inequality is oos

but consider the following totally non-oos derivation



the syllabus say "prove further results involving inequalities by logical use of previously obtained inequalities"

it would be bizarre to prove many things in the proofs topic, and then require that results therein proved not allowed to be subsequently used in other topics such as the q10 in 2024 hsc exam

no mathematician in the world does maths like this