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.
"A construction company is stringing up signs ... "
Divide 4 miles by 1/8 mile:
4 miles
--------------------------- = 32 signs are needed
(1/8) mile per sign
Step-by-step explanation:
x^2 +10x + 24
use FOIL
have a great day
This answer is Y=-1/2x+11 I believe
Answer:
(x-5)² + y² = 4
Step-by-step explanation:
formula of circle: (x-h)² + (y-k)² = r² where (h,k) is coordinate of center and r is radius
center: (5 , 0) r = 2
Equation: (x-5)² + y² = 4
