# Help with trig and radians

#### blue19

Fidn all the values of θ with θ_< θ< 2pi such that sin(3θ)= -0.5

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#### Ackbeet

MHF Hall of Honor
Two questions:

1. Is that $$\displaystyle 0<\theta<2\pi$$?
2. What have you done so far?

#### blue19

1. Yep that's right.
2. I haven't done anything yet.

#### Ackbeet

MHF Hall of Honor
Ok. You need to show the initiative on this forum. We'll help you get unstuck, but the rule is that people asking for help basically have to do the work. Otherwise, we're not helping you understand. So, show us some work, and we'll help you get unstuck.

mr fantastic

#### blue19

I honestly have no clue what to do, or where to start from to solve this problem.

#### Ackbeet

MHF Hall of Honor
Ok. Try plotting the function over the region indicated, and see where that leads you.

#### blue19

What do you mean by that :S

#### Ackbeet

MHF Hall of Honor
Plotting, graphing, whatever. Use a calculator or a computer to show a graph of the function over the interval from $$\displaystyle 0$$ to $$\displaystyle 2\pi$$.

#### blue19

I haven't got a calculator or computer program that can do this.

#### Ackbeet

MHF Hall of Honor
Ok. Go to Wolfram Alpha and try this on for size. That's obviously not the function you want, but you can get what you want. Trig functions must be typed as follows: cos(x) is typed as Cos[x].