Answer:
Step-by-step explanation:
Let's start with distributing: 
Simplify i with i in the second term, and rearrange.
. Since i in the denominator looks ugly, let's multiply top and bottom by i. 
. The middle passage is based on the fact that, by definition, 
cos (2x) = cos x
2 cos^2 x -1 = cos x using the double angle formula
2 cos ^2 x -cos x -1 =0
factor
(2 cos x+1) ( cos x -1) = 0
using the zero product property
2 cos x+1 =0 cos x -1 =0
2 cos x = -1 cos x =1
cos x = -1/2 cos x=1
taking the arccos of each side
arccos cos x = arccos (-1/2) arccos cos x = arccos 1
x = 120 degrees x=-120 degrees x=0
remember you get 2 values ( 2nd and 3rd quadrant)
these are the principal values
now we need to add 360
x = 120+ 360n x=-120+ 360n x = 0 + 360n where n is an integer
Answer:
is 
Step-by-step explanation:
var x = +3 (one side of right angled triangle)
var y = +1 (the other side of the right angled triangle)
Use the Pythagoras' Theorem.
3² + 1² = 10
D because it does not have shaded, it’s not shaded so it does not include 2, and 3 and up people need to join the club still for it to be official
