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:
Please look at the attachment for step by step guide and solution.
Answer:
8.66214 x 10^11
Step-by-step explanation:
question may ask to round, so the answer may be simplified to 9 x 10^11
C. For every decrease of one chore completed, one hour was spent on the internet.
Answer:
B: 4
Step-by-step explanation:
A trapezoid have 4 sides.
Hope it helps you in your learning process
