Tea.towel's Specialist Questions

[tea.squaredd]

Hi guys,

I'm taking specialist as a subject this year and there's bound to be questions that I'll get stuck on. So please help me guys !


Cheers!

Here's the 1st question:

z= 9acos(theta) + 4asin(theta)i, Find |z|

Sorry i dont know how to do those actual math signs on the forum yet.. !

[evaever]

|z|= sqrt((9acos(theta))^2 + (4asin(theta))^2), squaring whatever

[tea.squaredd]

Really? So the answer would be..
sqrt [81a^2cos^2(theta) + 16a^2sin^2(theta) ]
S:

[david10d]

disregard

[evaever]

you forgot i^2 = -1 which makes it:

sqrt [81a^2cos^2(theta) - 16a^2sin^2(theta)]

which then you can further factorise to:

sqrt [(9acos(theta)+4asin(theta)(9acos(theta)-4asin(thetic)]

are you sure that there's nothing left to the question? it just seems out of place lol

z=x+iy, |z|=Sqrt(x^2+y^2) NOT Sqrt(x^2-y^2)

[Dr.Lecter]

you forgot i^2 = -1 which makes it:

sqrt [81a^2cos^2(theta) - 16a^2sin^2(theta)]

which then you can further factorise to:

sqrt [(9acos(theta)+4asin(theta)(9acos(theta)-4asin(thetic)]

are you sure that there's nothing left to the question? it just seems out of place lol

z=x+iy, |z|=Sqrt(x^2+y^2) NOT Sqrt(x^2-y^2)

wtf wrong

[david10d]

oh shit. lol yeah my bad... relax it's the wee hours of the morning

now it seems that a has to equal to something to make the identity sin^2(A)+cos^2(A)=1

[pHysiX]

Now you can keep that answer or use the identity to make |z| entirely cos or sin

or

To learn the maths signs, use [t e x] <insert code> [/t e x] wrapper (without the spaces there).
For the code: http://www.maths.tcd.ie/~dwilkins/LaTeXPrimer/