Solving for x over interval [0, 2pi]

[tristatefabricatorsinc]

Solve for x over the interval [0 , 2pi]
1 + 1/2 cos x = 1/2


Here's what I have done so far... Not Sure if I am correct or not...

subtract 1 from both sides

1/2 cos x = -1/2

Divide both sides by 1/2 to get...

cos x = -1


Is this correct so far? Is the answer 3pi / 2 ?

 

[daveyp225]

When is cosine -1? Not at 3pi/2...

 

[tristatefabricatorsinc]

Oops, I don;t know why I did that, cos is x, so it is -1 at pi

So, for this question is it just pi as the answer?

It seems like all the other problems we have had like this have a solution set of 2 answers?

 

[daveyp225]

Pi is the only answer. There is no other value between 0 and 2Pi that makes cosine -1.