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:
10
Step-by-step explanation:
Answer:
Veronica's age now =8 years
Step-by-step explanation:
Veronica's age now = x years
Georgia's age now = 5x - 7
Veronica age after 6 year = 14
x + 6 = 14
x = 14 - 6
x = 8 years
B. Sandwich costs $7.70 and the soda costs $2.20
Answer:
A normal distribution with a mean of 0 and a standard deviation of 1 is called a standard normal distribution. so its A
Step-by-step explanation:
i looked it up and i think this is right :)
