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.
Answer:
45 degrees for 8
135 degrees for 9
48 for 10
Yes a square is a rectangle
Next ones.
Sut = 21 becuase x=5
7
Step-by-step explanation:
Last one:
x^2 + 8 = 3x + 36
- 8 - 8
x^2 = 3x + 28
-3x -3x
x^2 - 3x = 28
(x · x) - 3x = 28.
This was were a little guess work was used,
I found that any number lower than 7 is less than 28 when pluged into x and any above is higher.
Hence x = 7
So
x^2 + 8 = 7^2 + 8
7 x 7 = 49. 49 + 8 = 57.
and
3x+36 = 7 x 3 + 36
7x3 = 21. 21 + 36 = 57.
Both lines are equal so x is indeed 7.
The RSTU rectangle
3x+6 = 5x-4
+4 +4
3x+10 = 5x
-3x -3x
10 = 2x
10/2 = 5
5 = x or x = 5
plug it in now
3 x 5 = 15. 15 + 6 = 21
and
5 x 5 = 25. 25 - 4 = 21
so x = 5
8-10
QRS = 45 degrees because bisects the square with a diagonal line from corner to corner
PTQ is a 135 degrees because it is wider than a 90 degrees angle and meets both upper corner from the middle of the square making it 135 degrees.
SQ = 48 because RT = 24 and RT is half the length of SQ meaning its length would be 48
Or
SQ= 24 degrees because RT = 24 and if RT was to continue on the line it is on it will reach the length of SQ.
Eli will finish first.
Use 8/10 and 10/12. This represents how many spring rolls over how many minutes. Make your equations like this: 8/10 = 40/x and 10/12 = 40/x. Find x, which will give you the minutes it takes them to make 40 rolls.
You get x = 50 for the first one and x = 48 for the second. Nora makes 40 rolls in 50 minutes, and Eli makes 40 rolls in 48 minutes. Eli is faster.
Hope this helped! Please mark me brainliest!
Answer:
390.377
Step-by-step explanation:
pi*r^2
Rectangle: a = w x l
Square: a = a^2
Triangle: a= b x h divided by 2
Parallelogram: a = HH
Trapezoid: a = a+b
2h
