00:01
Okay, this i want to write in standard form, which means get all the eyes on top.
00:06
So, first thing then, 8 .i.
00:10
If i square the bottom, i will get 16 plus 40i plus 25 i squared.
00:20
Just do it as normal, like foil.
00:22
If i have a plus b all squared, it's a squared plus 2ab plus b squared.
00:27
So 4 squared is 16.
00:31
2 times 4 times 5 i is going to be 40 i and 5 i times 5 i squared.
00:43
Now i squared is negative 1.
00:48
So this item here is minus 1.
00:52
What i have then is 16 minus 25 which is minus 9.
00:59
So minus 9 plus 40.
01:02
Is on the bottom.
01:05
That's the first step.
01:07
I expand the bracket and simplify.
01:11
Now i want the eyes on top which means you multiply top and bottom by the same thing and that thing is the conjugate of the bottom.
01:21
Minus 9 minus 40i...