Analytical Geometry HW: 1.2.1, mPR & mRN Solutions

[DERRAN]

Homework Statement

http://img23.imageshack.us/img23/8680/68366634.gif


1.2.1 only!

Homework Equations

The Attempt at a Solution

m_PR=1/2
tan(1/2)=26.57

m_RN= -1/5
ref angle=11.32

R=11.32+26.57
=37.88

is it correct?

 

[Mark44]

Homework Statement

http://img23.imageshack.us/img23/8680/68366634.gif


1.2.1 only!

Homework Equations

The Attempt at a Solution

m_PR=1/2
tan(1/2)=26.57

m_RN= -1/5
ref angle=11.32

R=11.32+26.57
=37.88

is it correct?

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:

tan(1/2)=26.57

You can say that arctan(1/2) = 26.57 degrees, or that tan^-1(1/2) = 26.57 degrees, where both are approximations.
That