Question

Find all values of x such that sin (2x) = sin x and \(0 \le x \le 2\pi\).

How do I do this?

Answer 1

write sin2x as 2sinxcosx, then divide both sides by sinx, then divide by two, leaving cosx = 1/2. can you do it from there?

Answer 2

do i get the \(\cos^{-1}\) of 1/2?

Answer 3

yes, which has two values on the unit circle

Answer 4

my calculator says 60...

Answer 5

pi/3 or 5pi/3

Answer 6

expand sin(2x) and cancel out sin(x)

Answer 7

i get pi/3 equals 60...but where did 5pi/3 come from o.O

Answer 8

this MUST be in radians igbiw..