How do you solve $2(cosx+1)=1$ in the interval $0<=x<=2pi$ ?

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Answer 1 · 2016-11-05T10:54:37

In the interval $0<=x<=2pi ,x= (2pi)/3 and x= (4pi)/3$

$2(cosx+1)=1 or (cosx+1)=1/2 or cosx= -1/2$

In the interval $0<=x<=2pi , cos (pi-pi/3) = -1/2 and cos (pi+pi/3) = -1/2$

Solution : $x= (2pi)/3 and x= (4pi)/3$ [Ans]

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