00:01
Okay, we're given here three zeros, i, sorry, 1, 5i and negative 5i, which means it comes from this equation, x minus 1 times x minus 5i times x plus 5i equals 0.
00:20
That equation has those three roots or those three zeros.
00:26
And i want to work out a function on the left.
00:30
What do i do? well, x minus 1.
00:35
And if i multiply these two together, it's like doing x minus a times x plus a, it's x minus a squared.
00:46
So here then will be x squared minus 25 i squared.
00:53
If i work it out, let's use simple foil.
00:57
Or is known the formula for a minus b times a plus b.
01:02
Equals 0.
01:05
So what we have now then is x minus 1, x squared, or i squared is negative 1...