00:04
We're asked to prove a statement involving complex numbers.
00:09
So given any two complex numbers, z and w, in part one, we're asked to prove that the conjugate of z plus w is the conjugate of z plus the conjugate of w.
00:29
In other words, conjugation distributes over addition.
00:36
So in order to prove this, first let's write z and w in standard form.
00:40
So we'll say that z is equal to a plus b i and w is equal to c plus d i for some constants ab c and b now we have the conjugate of z plus w this is the conjugate of the imaginary number a plus c sorry complex number a plus c b plus d i and the conjugate of this number well this is the same number with the opposite sign for the imaginary part so this is a plus c minus b plus d i and then distributing the negative we get a minus b i we regroup plus c minus d i and this is clearly the conjugate of a plus b i plus the conjugate of c plus d i we flip the signs of the imaginary parts, and this is equal to the conjugate of z plus the conjugate of w.
01:56
So we've proved statement one.
02:00
Now statement two, this says that the conjugate of z times w is equal to the conjugate of z times the conjugate of w.
02:07
Or in other words, you could say that conjugation distributes over multiplication of complex numbers.
02:15
To begin with the left -hand side, the conjugate of z times w, so this is the conjugate of of a plus b -i times c plus d -i...