Question

can someone please show me how to do this?
solve the equation: 2cosx+1=0

Answer 1

cos x = -1/2

so can you tell me the values of x satisfying the above eq in the range[0, 2pi)?

Answer 2

\[2 \cos x +1 = 0\]\[2 \cos x =-1 \]Divide 2 on both sides,
\[\cos x = -\frac12\]Then follow above^

Answer 3

thank you

Answer 4

So why are you reposting this?

Answer 5

i'm not sure what to do after cosx=-1/2

Answer 6

Are you familiar with the unit circle?

Answer 7

yes

Answer 8

And you know that the cosine is like x?

Answer 9

yes

Answer 10

So find the two angles on the unit circle which have x coordinate - 1/2

Answer 11

11pi/6 and 7pi/6?