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chocolatelover

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## Homework Statement

Each of the displacement vectors A and B have a magnitude of 3.00 m. Vector B is vertical and is on the y axis, vector A forms a 30 degree angle to the positive x axis. Report all angles counterclockwise from the positve x axis. Find A+B, A-B, B-A, A-2B

This is similar to what the diagram looks like:

http://id.mind.net/~zona/mstm/physics/mechanics/vectors/components/vectorComponents.html

## Homework Equations

magnitude=square root(Ax+Bx)^2+(Ay+By)^2

theta=tan-1(Ay+By/Ax+Bx)

## The Attempt at a Solution

1. A+B

magnitude=square root (3cos30+3cos90)^2+(3sin30+3sin90)^2

=2.7

theta=tan-1(3sin30+3sin90)/(3cos30+3cos90)=69.4

2. A-B

magnitude=square root (3cos30+3cos90)^2+-(3sin30+3sin90)^2=square root (-13.5) This then goes to 3.67, right?

theta=tan-1(3sin30+-3sin90)/(3cos30+-3cos90)=19.05

3. B-A

theta=tan-1(sin90-3sin30)/(3cos30-3cos90)=74.4

4. A-2B

magnitude=square root(3cos30+3cos90)^2+-(2(3sin30+3sin90)^2=5.8

theta=tan-1(3sin30-2(3sin30+3sin90)/(3cos30+-2(3cos30+3cos90)

I would really appreciate if someone could help me with these 4 parts. I've been working on this for two days and I don't understand it. I don't see what I'm doing wrong.

Thank you very much

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