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:
502.4
Step-by-step explanation:
Use tangent because the side you know and the side with x are both legs.
Do 203/tan(22) and you should get your awnser.
You devide by 203 because the rule is opposite over ajacent and 203 is the opposite side.
Answer:
X = -15
Step-by-step explanation:
6X +12 = 4X -18
Subtract 4X from both sides
2X +12 = -18
Subtract 12 from both sides
2X = -30
Divide both sides by 2
X = -15
So basically just have the unknown on one side and normal numbers on the other. Make sure you do the same thing on both sides.
Mark me as brainliest if this helps!
