The equation gives {TAIL ~ the dynamic relation} between the voltage U at and the power P through a connection to {HEAD ~ the load} 
The equation gives { TAIL ~ the dynamic relation } between the voltage U at and the power P through a connection to { HEAD ~ the load }
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD