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# Mechanics 1 help Watch

1. I have been working on this problem for about an hour and can't seem to get a solution. Can anyone help?

Two forces P and Q have magnitudes 3N and 6N respectively and act at point O. The angle between P and Q is acute. The resultant is R which makes an angle of 20 degrees with Q. Find the angle between P and Q and the magnitude of R.

All I've done is get the equations:
3sin(x) = Rsin20
3cos(x) + 6 = Rcos20

Some rearranging got me as close as
Tan20 = sin(x) / cos(x)+2
But I still can't get a solution.
2. (Original post by Bobrey)
I have been working on this problem for about an hour and can't seem to get a solution. Can anyone help?

Two forces P and Q have magnitudes 3N and 6N respectively and act at point O. The angle between P and Q is acute. The resultant is R which makes an angle of 20 degrees with Q. Find the angle between P and Q and the magnitude of R.

All I've done is get the equations:
3sin(x) = Rsin20
3cos(x) + 6 = Rcos20

Some rearranging got me as close as
Tan20 = sin(x) / cos(x)+2
But I still can't get a solution.
If you multipy up, and then square both sides, you can get a quadratic in cos x

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