mx1 and mx2 questions thread (PLEASE STAY ON TOPIC FOR JSUT THIS THREAD PELAS PELASE PEALSEPE) (1 Viewer)

[synthesisFR]

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did i do something stupid bc i solved it using the second method
but shouldnt there be two inequalities like the second like
i got 1-<x<1 and x<-1 x>-1/3 so u combine them
but the solution is diff
not sure what i did wrong

And this using the second method im so confused

 

[carrotsss]

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this might be a dumb qquestion but when they dot product it
why dont they like flip it so BA.BC bc the angle is from point B yeah
But they still do AB.CB which is like them facing each other but i was taught the vectors need to face away
the answer u get is still the same but i was just wondering if that is ok to do if they are facing each other
mathematically it works bc BA is just negative AB so it cancels out anyways but like in terms of like working out yk?
(dont mine the solutions idk why they uploaded it upside down )

it just doesnt matter, if u draw out the vectors beyond their line youll see that they create the exact same angle

 

[synthesisFR]

it just doesnt matter, if u draw out the vectors beyond their line youll see that they create the exact same angle

Yeah true true so as long as they r both point away or together it’s fine

 

[chilli 412]

View attachment 39587View attachment 39588
this might be a dumb qquestion but when they dot product it
why dont they like flip it so BA.BC bc the angle is from point B yeah
But they still do AB.CB which is like them facing each other but i was taught the vectors need to face away
the answer u get is still the same but i was just wondering if that is ok to do if they are facing each other
mathematically it works bc BA is just negative AB so it cancels out anyways but like in terms of like working out yk?
(dont mine the solutions idk why they uploaded it upside down )

shits upside down bro

 

[SadCeliac]

can someone please explain the solution for part ii???

why do we sub x = z/(z-1) ???
@carrotsss @synthesisFR ??

 

[synthesisFR]

View attachment 39607
can someone please explain the solution for part ii???

why do we sub x = z/(z-1) ???
@carrotsss @synthesisFR ??

It’s just to make it easier to solve
When u put everything on one side and then sun it as x u get an easier roots of unity
Then u just sub back and exclude the solution where is equal to one cuz that’s impossible

 

[SadCeliac]

It’s just to make it easier to solve
When u put everything on one side and then sun it as x u get an easier roots of unity
Then u just sub back and exclude the solution where is equal to one cuz that’s impossible

ok thanks

and if it were something like
z^4 = (z-2)^4

we would sub x = z/z-2 ????

im assuming that's where it comes from, right?

 

[ZaoKai]

can anyone explain a) ii) beta) for me? I am having trouble in visualsing the arg(z3-z2) and arg(z-1) (I am not sure where those angles are in the diagram) and how does the difference by pi/2 prove it's tangent

 

[carrotsss]

ok thanks

and if it were something like
z^4 = (z-2)^4

we would sub x = z/z-2 ????

im assuming that's where it comes from, right?

look at the LHS of the solution it’s basically just what’s in the brackets

 

[SadCeliac]

look at the LHS of the solution it’s basically just what’s in the brackets

but what I said is right? if we're doing z^4 = (z-2)^4 we sub x = z/z-2

i assume yes because you liked it lol

 

[synthesisFR]

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ik this is mcq but if it was show then C, how would u set it out?

please help ^^



could someone explain their explanation for Zmax? i get how to do it and the circle geo behind it but i just don't understand their explanation specifically the "places the centre at the origin". but like i do understand how its 90 in the centre then 45 outside.
is circle geo even in syllabus and assessable?

 

[synthesisFR]

please help ^^


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could someone explain their explanation for Zmax? i get how to do it and the circle geo behind it but i just don't understand their explanation specifically the "places the centre at the origin". but like i do understand how its 90 in the centre then 45 outside.
is circle geo even in syllabus and assessable?

@carrotsss

 

[carrotsss]

please help ^^


View attachment 39686View attachment 39687
could someone explain their explanation for Zmax? i get how to do it and the circle geo behind it but i just don't understand their explanation specifically the "places the centre at the origin". but like i do understand how its 90 in the centre then 45 outside.
is circle geo even in syllabus and assessable?

that explanation is confusing af, I got no clue sorry. never seen something like that before, idt that’s in the syllabus may be weong

 

[synthesisFR]

that explanation is confusing af, I got no clue sorry. never seen something like that before, idt that’s in the syllabus may be weong

wtf aren't u meant to be state ranking maths im dissapointed

 

[carrotsss]

View attachment 39583
ik this is mcq but if it was show then C, how would u set it out?

You could replace sin(alpha) with cos(alpha-pi/2) I guess, I highly highly doubt they’d actually do a full show question on that though it’s just basic assumed knowledge

 

[carrotsss]

wtf aren't u meant to be state ranking maths im dissapointed

i doubt it I think my teachers are being a bit optimistic

 

[synthesisFR]

You could replace sin(alpha) with cos(alpha-pi/2) I guess, I highly highly doubt they’d actually do a full show question on that though it’s just basic assumed knowledge

but the identity is pi/2 - alpha
how would u adjust it for the required quadrant and get alpha - pi/2

 

[carrotsss]

but the identity is pi/2 - alpha
how would u adjust it for the required quadrant and get alpha - pi/2

yeah that’s it it’s just quadrants, ig for a show question you’d have in brackets (alpha is in the second quadrant)

 

[synthesisFR]

help why can't i picture this diagram in my head

 

[synthesisFR]

HELP