# Thread: eb 4.d determine the magnitude and direction of V

1. $\tiny{\\ eb 4.d}$
$\textsf{If$v_x=-9.80$units and$v_y=-6.40$units,}\\$
$\textit{determine the magnitude and direction of$V$.}$
\begin{align*}\displaystyle
magnitude&=\sqrt{(-9.8)^2+(-6.4)^2}
=\color{red}{11.7047}\\
direction&=\arctan{\left[\frac{6.4}{-9.8}\right]}
=\color{red}{33.15^o}
\end{align*}

ok the direction is actually in the Q4 but $\arctan{\left[\frac{-6.4}{-9.8}\right]}$
is in Q1! Do we just add $180^o$ for that or is it $-33.15^o$

Also is there symbols for magnitude and direction other than an arrow on the graph

Also where is the latex for degree instead of ^o

2. Originally Posted by karush
$\tiny{\\ eb 4.d}$
$\textsf{If$v_x=-9.80$units and$v_y=-6.40$units,}\\$
$\textit{determine the magnitude and direction of$V$.}$
\begin{align*}\displaystyle
magnitude&=\sqrt{(-9.8)^2+(-6.4)^2}
=\color{red}{11.7047}\\
direction&=\arctan{\left[\frac{6.4}{-9.8}\right]}
=\color{red}{33.15^o}
\end{align*}

ok the direction is actually in the Q4 but $\arctan{\left[\frac{-6.4}{-9.8}\right]}$
is in Q1! Do we just add $180^o$ for that or is it $-33.15^o$
The direction would be in quadrant III, and so recognizing that both components are negative, you would in fact add $\pi$ to the angle:

$\displaystyle \theta=\pi+\arctan\left(\frac{v_y}{v_x}\right)$

Originally Posted by karush
Also is there symbols for magnitude and direction other than an arrow on the graph

Also where is the latex for degree instead of ^o
I use ^{\circ} for the degree symbol.

Originally Posted by MarkFL
The direction would be in quadrant III, and so recognizing that both components are negative, you would in fact add $\pi$ to the angle:

$\displaystyle \theta=\pi+\arctan\left(\frac{v_y}{v_x}\right)$
$\textsf{ok so it}$ $\displaystyle 33.15^\circ + 180^\circ = 213.15^\circ$
that would place it Q3

Originally Posted by MarkFL
I use ^{\circ} for the degree symbol.
actually why don't we have \degree on the Symbol/Command Set:

4. It was an oversight I suppose, but adding it now would require a lot of effort.