Question 1201409
.
a.
--> --> -->
PQ - RQ + RS
b.
--> --> --> -->
PS + RQ - RS - PQ
~~~~~~~~~~~~~~~~~~~~~~~~~~~


<pre>
(a)  PQ - RQ + RS = PQ + QR + RS = PS  ,  according to the base rule of addition vectors.



(b)  PS + RQ - RS - PQ = PS + RQ + SR + QP = (re-group addends) = PS + SR + RQ + QP = 0  (zero vector, since we have a closed contour).
</pre>


&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;If I understand it correctly, &nbsp;it is in the style of &nbsp;April-1 Math jokes . . . 


&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I like this joke: &nbsp;it is in a right style.



Thanks for posting it . . .