I'm stuck on this question as well so plz ppl answer xD
Answer:
What do you need help with?
Step-by-step explanation:
Answer:
Step-by-step explanation:
hello :
6x+5y=-20.....(*)
-6x-10y=25.....(**)
add(*) and(**) : -5y=5 so y= -1
multiply (*) by 2 : 12x+10y=-40 ...(***)
now add(**) and (***) : 6x=-15 so x = -15/6 = -5/2
we need some barriers such that total of length of all barriers should equal to the circumference of the circle.
so lets assume we need x barriers
then total length of all barriers = 2.5x meter
now radius of circular path = diameter / 2= 13/2 = 6.5 meter
circumference of path = 2× pi × r = 2 × 3.14 × 6.5
=40.82 meter
so now as per statement
2.5x = 40.82
x = 40.82/2.5 = 16.328 ≈ 17
so approximately 17 barriers are required
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.