4. Given the system equations a. Using only amplifiers and integrators draw a signal-flow graph representation of the system where U(s) is the input and X2(s) is the output. You

may assume zero initial conditions. b. Find the transfer function X2(s)/U(s) using Mason's Gain formula. Check your result using an algebraic approach. \frac{d x_{1}}{d t}=x_{1}+5 x_{2} \frac{d x_{2}}{d t}=2 x_{1}+u