Phasor Notation: Two sinusoidal signals are defined as x_{1}(t)=\sqrt{5} \cos (7 t-\pi / 3) \quad x_{2}(t)=\sqrt{5} \cos (7 t+\pi) \text { and their sum is denoted as } x(t)=x_{1}(t)+x_{2}(t) \text

{ a) Find the complex valued signal } z_{1}(t) \text { such that } x_{1}(t)=\Re\left\{z_{1}(t)\right\} \text { Find the complex valued signal } z_{2}(t) \text { such that } x_{2}(t)=\Re\left\{z_{2}(t)\right\} \text { Find the complex valued signal } z(t) \text { such that } x(t)=\Re\{z(t)\}