which value of x gives you sin(3(x+120)°) = 1/2

Question

which value of x gives you sin(3(x+120)°)  = 1/2

anonymous · Answer

oops sorry a)170 b)175 c)180 d)185

ash2326 · Answer

Let's simplify the term inside the sine
$$\sin (3(x+120))=\frac 12$$
$$\sin (3x+360)=\frac 12$$
We know that sine has a period of 360 degrees or $\pi$ radians, so 
$$\sin (3x+360)=\sin 3x$$
Now we get
$$\sin (3x)=\frac 12$$
Hey @bronzegoddess for what value of angle is sin      $\frac 12$??

anonymous · Answer

30 or $$\Pi/6$$

anonymous · Answer

@ash2326  where did this come from?sin(3x+360)=sin3x

ash2326 · Answer

@bronzegoddess it's the property of all the tangent functions, they repeat their value after a period of 360 or $2\pi$.
Sorry I missed the 2 earlier

anonymous · Answer

i know but then you just remove it from the equation?

ash2326 · Answer

|dw:1341244602015:dw| o and 360 come at the same point, so if we have 
sin 390= sin 30
yeah, you can remove it just like that