Complex Numbers/Vectors test…

For friday…
Are we allowed log book? log books? (then i can use both this yrs and last years log book)
are we allowed calculator? Graphics calculator?
and how do i do this…? I feel dumb…
Chapter Review 1
if a = 2i-3j+k
if b = -2i+3j+k
What is the unit vector that is both perpendicular to a and b
the answer is 1/root(13) x (3i+2j) or the anti-parallel of that unit vector
I just have no idea what to do… tried dot product, wierdo vector algebera…

How to work this out?

I decided to start holiday work with spesh i finally got stuck
Q7 from page 66, chapter 2.7
“Given that cis 3θ = (cos3θ – 3 cos θ sin2θ) + i (3 cos2θ sin θ – sin3θ), it follows that cos3θ is equal to:”
the answer is D, which is… 4 cos3
θ – 3 cos θ
how is that the answer? HOW IS THiS demoivre’s theorem? what is this?
enjoy the rest of the short holidays! dipole

New Authors

Hi Spec class…

Yes, I’ve changed the look – what do you think? Also, if you give me your email addresses (in class not on the site!!) I will add you as authors to the site so you can write your own posts. In wordpress you can then use superscripts 2 and other special characters to enhance the maths!!

Kevin, you have already been added, just answer the email that should have come your way, and then start posting.

(a(x – 3))2 = cos(πθ)c , etc

Mr K