Answer:
y= mx + b
y = 4x +3
Step-by-step explanation:
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 B.
Step-by-step explanation:
Answer:
y = 2
Step-by-step explanation:
varies inversely
xy = k
y = 7 when x = 2/3
(2/3)7 = k
14/3 = k
k = 14/3
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find y when x = 7/3
(7/3)y = 14/3
multiply both sides by 3/7
y = 14/3 * 3/7
y = 2
