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:
the answer is a b and d
Step-by-step explanation:
I took the quiz
This is how i worked it out.
Good Luck
Answer:19683x
Step-by-step explanation:
Evaluate the exponent
27.93x
27.729x
i am pretty sure sorry if I am wrong
$2.50+3x=$9.25, if you need to work it out, then you do $9.25-$2.50. You take your answer and divide by three... whatever your solution is, equals X. There you go!
