The multiplicative inverse of a number is the number when you multiply it, it gives you the product of 1.
So for - 27, what number will give us 1 when we multiply it by -27
-27 * -1/27 = 1
So the multiplicative inverse of -27 = -1/27
7/9 * 9/7 = 1
-9/16 * -16/9 = 1
So in essence, just take the number and flip it
-27 = -1 / 27
7/9 = 9/7
-9/16 = -16/9
Answer: I think 7
Step-by-step explanation:
Answer:
Step-by-step explanation:
Firstly, note that -2i really is just z = 0 + (-2)i, so we see that Re(z) = 0 and Im(z) = -2.
When we're going from Cartesian to polar coordinates, we need to be aware of a few things! With Cartesian coordinates, we are dealing explicitly with x = blah and y = blah. With polar coordinates, we are looking at the same plane but with angle and magnitude in consideration.
Graphing z = -2i on the Argand diagram will look like a segment of the y axis. So we ask ourselves "What angle does this make with the positive x axis? One answer you could ask yourself is -90°! But at the same time, it's 270°! Why do you think this is the case?
What about the magnitude? How far is "-2i" stretched from the typical "i". And the answer is -2! Well... really it gets stretched by a factor of 2 but in the negative direction!
Putting all of this together gives us:
z = |mag|*(cos(angle) + isin(angle))
= 2*cos(270°) + isin(270°)).
To verify, let's consider what cos(270°) and sin(270°) are.
If you graph cos(x) and look at 270°, you get 0.
If you graph sin(x) and look at 270°, you get -1.
So 2*(cos(270°) + isin(270°)) = 2(0 + -1*i) = -2i as expected.
Step-by-step explanation:
what concepts of functions can you associate with the picture
