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URGENT

2π/3&5π/3

Step-by-step explanation:

2 cos(x)+1=0

i.e, cos(x) =(-1/2)

i.e, cos(x)= - cos (π/3)

i.e, cos(x)= cos(π-π/3) [since, cos(π-x) = -cosX]

i.e, cos(x)=cos2π/3

x=2π/3

or, cos(x)= -cos(π/3)

i.e, cos(x)=cos(π+π/3). [since, cos (π+x)= -cosx]

x=4π/3

✌️:)

Circumference - 2 * pi * r

Step-by-step explanation:

multiply radius by 2.

multiply by pi