Maths Extension 2 Predictions/Thoughts (1 Viewer)

[gunnerfan99]

its b. B does not have a definitive frequency for shm

A is actually periodic in pi

Fuck

 

[thomas mcnamee]

if you start with two polars being the same, the implication that their values of theta are the same is wrong.

e.g. exp(i pi/2) = exp(i 5pi/2) but pi/2 does not equal 5pi/2

but r is real?

 

[notme123]

but r is real?

they both have r as 1

 

[synthesisFR]

wait but like for 7
how is it b? if
theta = pi, and pi/2 then u get arg (theta1theta2) as 3pi/2 which is not principal arg? thats why i put C

 

[scaryshark09]

but r is real?

r has nothing to do with it

 

[notme123]

wait but like for 7
how is it b? if
theta = pi, and pi/2 then u get arg (theta1theta2) as 3pi/2 which is not principal arg? thats why i put C

the answer is A for 7

 

[pdawg]

its b. B does not have a definitive frequency for shm

A is actually periodic in pi

what if theta1 is pi/2 and theta2 is 2pi/3. Arg(z1z2) would be equal to -5pi/6 and theta1 + theta2 = 7pi/6. am i stupid or sum

 

[gunnerfan99]

I think 10 is B

 

[scaryshark09]

Arg(ab) = Arg(a) + Arg(b)
that is the formula you have to use i think
thats how i got b

 

[pdawg]

the answer is A for 7

rip

 

[notme123]

tan(theta) = y/x does imply x + iy = rexp(itheta) for only ONE solution of tan(theta) = y/x

its which solution that matters but its irrelevant for this question because its in the 'if' part, not the 'then' part

 

[synthesisFR]

wtf
A says "for some real number r" but r has to be positive which is why i didn't pick A...

 

[synthesisFR]

Arg(ab) = Arg(a) + Arg(b)
that is the formula you have to use i think
thats how i got b

yeah but like does this counter example not disprove it since the final arg is not principal which is what the question states..

wait but like for 7
how is it b? if
theta = pi, and pi/2 then u get arg (theta1theta2) as 3pi/2 which is not principal arg? thats why i put C

 

[synthesisFR]

ok bye i basically failed it hink

 

[gunnerfan99]

you know it clearly was a good multiple choice that its led to such debate from people who genuinely love maths enough to do papers on the day they are released.

 

[notme123]

wtf
A says "for some real number r" but r has to be positive which is why i didn't pick A...

r doenst have to be positive

 

[synthesisFR]

you know it clearly was a good multiple choice that its led to such debate from people who genuinely love maths enough to do papers on the day they are released.

not its because people like me r depressed bc we did clearly horrible

 

[gunnerfan99]

not its because people like me r depressed bc we did clearly horrible

you will be surprised mate

 

[notme123]

heres an example,

tan(-pi/4) = 1/-1 which implies that -1+i = r*exp(-i pi/4) but only when r = -sqrt(2)

 

[Hudz777]

yeah 6 is B for sure