Should be (3,2)
You only need to inverse your x coordinate.
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.
Since we don't have a figure we'll assume one of them is right and we're just being asked to check if they're the same number. I like writing polar coordinates with a P in front to remind me.
It's surely false if that's really a 3π/7; I'll guess that's a typo that's really 3π/4.
P(6√2, 7π/4) = ( 6√2 cos 7π/4, 6√2 sin 7π/4 )
P(-6√2, 3π/4) = ( -6√2 cos 3π/4, -6√2 sin 3π/4 )
That's true since when we add pi to an angle it negates both the sine and the cosine,
cos(7π/4) = cos(π + 3π/4) = -cos(3π/4)
sin(7π/4) = sin(π + 3π/4) = -sin(3π/4)
Answer: TRUE
Answer:
I agree with Emma
Step-by-step explanation:
above
A) - 14 is the correct answer
