# Homework Help: Analytical geometry

1. Jun 15, 2009

### DERRAN

1. The problem statement, all variables and given/known data

http://img23.imageshack.us/img23/8680/68366634.gif [Broken]

1.2.1 only!!!!
2. Relevant equations

3. The attempt at a solution
mPR=1/2
tan(1/2)=26.57

mRN= -1/5
ref angle=11.32

R=11.32+26.57
=37.88

is it correct?

Last edited by a moderator: May 4, 2017
2. Jun 15, 2009

### Staff: Mentor

I don't think so. The problem asks for $$\hat{R}$$. The caret (or "hat") is usually interpreted to mean a unit vector, but that's probably not what is meant here, since the magnitude of any unit vector is 1. I think that what is asked for is the magnitude of the vector from O to R. You seem to have calculated the measure of angle PRQ. Since it's not clear to me what $$\hat{R}$$ is intended to represent, it's unclear to me what this problem is asking you to do.

Your calculation of the slope of PR is correct, but this isn't:
You can say that arctan(1/2) = 26.57 degrees, or that tan-1(1/2) = 26.57 degrees, where both are approximations.
That

Last edited by a moderator: May 4, 2017