$O P = V _ { 1 } ^ { 2 } + V _ { 2 } ^ { 2 } + 2 \left( V _ { 1 } \right) \left( V _ { 2 } \right) \cos \theta$

Short Answer

$O P = V _ { 1 } ^ { 2 } + V _ { 2 } ^ { 2 } + 2 \left( V _ { 1 } \right) \left( V _ { 2 } \right) \cos \theta$ Two voltages ( $E _ { 1 }$ and $E _ { 2 }$ ) are applied to a resister. $$E _ { 1 }$$ is 40 volts at $0 ^ { \circ }$ reference. $E _ { 2 }$ is 60 volts and leads $E _ { 1 }$ by $40 ^ { \circ }$ . Find $E_ R$ to the nearer tenth.