00:01
All right, and your question, you're asked to write the rectangular form of 6 cis 210 degrees.
00:11
Well, what that actually is, this can be called trig form or polar form.
00:18
What it actually stands for, the cis abbreviation stands for cosine of the angle plus i sign of the angle.
00:26
So all we need to do is figure out the value of cosine of 210.
00:30
Now, it's very beneficial for you to have had.
00:33
That memorized.
00:34
But if you don't, you look it up on a unit circle, cosine of 210.
00:40
There's the 210 degree angle.
00:42
Cosine is your x coordinate.
00:45
So negative three, negative square root of three over two.
00:52
We have the six negative square root of three over two plus i.
00:59
And now we need sign of 210...