I have A + B = 1 i - 8 j, and |A + B| = 8.06,Consider two vectors by A = 2 i - 2 j and B = - i - 6 j.
1) What is the direction of A + B? (from the +x axis)
what i need to do to get the direction?
The angle is determined by $\displaystyle \vartheta=\tan^{-1}\left(\frac{v_y}{v_x}\right)$, where $\displaystyle v_x~and~v_y$ are the components of a vector $\displaystyle \vec{v}$
So, in our case, $\displaystyle \vec{A}+\vec{B}$ (which I will denote as $\displaystyle \vec{V}$) is $\displaystyle \vec{i}-8\vec{j}$
Thus, $\displaystyle \vartheta=\tan^{-1}\left(\frac{-8}{1}\right)\approx\dots$
I hope this helps!
--Chris