+0

# Complex Numbers

0
193
1

If Q = 11 - 5i, E = 3 - 2i, and D = 2i, find QED.

Aug 29, 2021

#1
+631
0

I'm going left to right with the multiplication. Q is across the top, E is down the left.$$\left.\begin{matrix} &11&-5i\\ 3&33&-15i\\ -2i&-22i&-10 \end{matrix}\right] = 23 - 37i$$.

Now, we multiply QE by D. $$(23-37i) \times 2i = QE \times D = QED = 46i + 74$$.

Remember, i * i = -1, and -i * i = 1. i is effectively a variable until you are dealing with more than one of them being multiplied.

I think the term for this is "abstract quantity"? It's a value you use like a variable with some exceptions.

Aug 30, 2021