By performing cascading and/or summing/differencing operations using transfer function blocks $G_{1}(s )$ and $G_{2}(s),$ one CANNOT realize a transfer function of the form
- $G_{1}(s)G_{2}(s) \\$
- $\dfrac{G_{1}(s)}{G_{2}(s)} \\$
- $G_{1}(s)\left(\dfrac{1}{G_{1}(s)} + G_{2}(s)\right) \\$
- $G_{1}(s)\left(\dfrac{1}{G_{1}(s)} - G_{2}(s)\right)$