I don't undestand these trig angle questions at all.

Find theta, 0 < theta < 2pi, if tan theta= 0.66

Find theta, 0 < (or equal to) theta < (or equal to) 360 if cos theta= -0.89

Am I over-thinking these questions or does it actually have an extensive answer? To me, my guess is for 1, to do .66 tan-1 and for 2, to do -0.89 cos-1, but that seems to simple.

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Originally Posted by ChrisTurner91

Find theta, 0 < theta < 2pi, if tan theta= 0.66
Find theta, 0 < (or equal to) theta < (or equal to) 360 if cos theta= -0.89
Am I over-thinking these questions or does it actually have an extensive answer? To me, my guess is for 1, to do .66 tan-1 and for 2, to do -0.89 cos-1, but that seems to simple.

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For the first there are two answers: .

What are the two for the second part?

arccos(-0.89) and arccos(-0.89) + pi?

So I'm just using the inverse function to solve for it?

Quote:

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Originally Posted by ChrisTurner91

arccos(-0.89) and arccos(-0.89) + pi?
So I'm just using the inverse function to solve for it?

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No there is far more to it than that.
First note that the question asks for the answer in degrees.
So you must convert to degrees.
That answer will be in quad-II.

The second will be in quad-III with the same reference angle as the the first.