00:01
Okay, so we want to find our cube roots of i.
00:04
Well, that means that we have n is equal to dream, since we want to find the cube roots, and let's rewrite i in terms, or in chug form.
00:11
So that's just going to be cis of 90 degrees.
00:16
So let's use our nth root theorem.
00:19
So that's going to be the third roots of r, which is one.
00:23
And then we have cis of alpha, but that's equal to cis of alpha, where alpha is equal to our data value, that's 90 degrees, plus 3, 160 degrees times k over our n value.
00:37
So it's 90 over 3.
00:39
That's equal to 30 degrees plus 360 divided by 3, which is 120 degrees times k.
00:48
And this is for k is equal to 0, 1 and 2.
00:51
So let's find our 3 roots.
00:53
So when k is equal to 0, we're going to have cis of alpha, given that k is equal to 0.
01:01
So that's this 30 degrees.
01:03
So cosine of 30 degrees...