1 + cosx + cos2x=0 help my math xD ty

x = π/2 + nπ or x = (2/3 π + 2nπ) or x = (4/3 π + 2nπ)

Step-by-step explanation:

1 + cosx + cos2x=0

1+cosx+(2cos²x -1) = cosx + 2cos²x = cosx (1 + 2cosx) = 0

cosx = 0    

x = 90° (π/2) or (90+180) or (90+180x2) i.e    π/2 + nπ

or 1 + 2cosx = 0

cosx = -1/2

x = 120° or 240°  (2/3 π or 4/3 π)  or (120 + 360 : 2/3 π + 2π) (120 + 2 * 360)

i.e. (2/3 π + 2nπ)

or (240 + 360 : 4/3 π + 2π) (240 + 2 * 360) i.e. (4/3 π + 2nπ)

the best buy, is the 4- kilogram bag of lollipops for $18.40.

step-by-step explanation:

i found my answer by dividing the cost of each bag by their respective weights.

14.88 divided by 2 = 7.44

17.29 divided by 3 = 5.77

18.4 divided by 4 = 4.6

24.4 divided by 5 = 4.88

by this, i found that the 4 kilo bag is the best buy.

  y= -3x is the required function.

step-by-step explanation:

we have been given a table:

x             y

0             0

1             -3

3             -9

-2             6

we can see that the values of y is -3 times the value of x

hence, the function would be: y= -3x.

put the values of x will give the same y as in the table that means function is satisfying the given table.