Questions - Baulkham Trial Paper (1 Viewer)

[scaryshark09]

How do you do part (ii) and (iii) please?

 

[synthesisFR]

View attachment 40539
How do you do part (ii) and (iii) please?

they should have solutions..
i did this paper a while ago tho:
ii) is just the identity where modulus square is the complex and the complex conjugate multiplied and then u get that basically. (PAk is the same as AkP so u get P - Ak which is Z - wk)
iii) u need to sum it and then expand to get each quadratic z thing and simply it and it yields the answer

 

[scaryshark09]

for part (iv), i did the intgration without bounds and did the plus c thing, and then subed values in to find c. In this case it didn't work. Can someone explain why you have to integrate with bounds for part (iv), or is there something i am missing?

 

[scaryshark09]

ii) is just the identity where modulus square is the complex and the complex conjugate multiplied and then u get that basically. (PAk is the same as AkP so u get P - Ak which is Z - wk)

ive either never heard of this identity or forgot about it. is it in the cambrige textbook?

 

[Average Boreduser]

View attachment 40539
How do you do part (ii) and (iii) please?

for both II and III can you use the |z|^2 identity? (ie |z|^2=z*z(conjugate))?

 

[Average Boreduser]

ive either never heard of this identity or forgot about it. is it in the cambrige textbook?

Its apparently something ppl always manage to forget in 4u. similar to that triangle inequality thingo (NOTE I DONT MEAN THE IDENTITY IS RELATED TO IT, IM SIMPLY SAYING THAT ITS AS FORGOTTEN AS THE TRIANGLE INEQUALITY)

 

[scaryshark09]

for part (ii), i think the answer is pretty self-explanatory as Ar <= Br. but how do you even prove it, the solutions kinda just stated it

 

[scaryshark09]

View attachment 40539
How do you do part (ii) and (iii) please?

why does PAk = z-wk tho?

 

[scaryshark09]

oh dw, synthesis explained it

 

[scaryshark09]

View attachment 40541
for part (iv), i did the intgration without bounds and did the plus c thing, and then subed values in to find c. In this case it didn't work. Can someone explain why you have to integrate with bounds for part (iv), or is there something i am missing?

dw about this i just made a mistake

 

[synthesisFR]

what mark did.u get

 

[scaryshark09]

ill dm

what mark did.u get

 

[Luukas.2]

ive either never heard of this identity or forgot about it. is it in the cambrige textbook?

Yes, the identity is in all the texts, and is easily proved.

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