Given the vector u → = 〈 - 5 , - 1 〉 , find the magnitude and angle in which the vector points (measured counterclockwise from the positive x-axis, 0 ≤ θ < 2 π

Answer 1

<-5,-1> has an angle with the x axis a little more than pi radians

sketch a graph and plot the point (-5,-1)

arctan(-1/-5) = about 11.31 degrees

add to 180 to get 191.31 degrees

multiply by pi/180 to get about 1.07 pi radians

magnitude = d

where d^2 = 5^2+1^2 =26

d=sqr26 = about 5.1