求解 {l}{y=3+4t+2t^2}{z={(d/dt{{(y)}})}}{a=z}{b=a}{c=b}{text{Solvefor}dtext{where}}{d=c}

$$\left. \begin{array} { l } { y = 3 + 4 t + 2 t ^ {2} }\\ { z = {(\frac{d}{dt} {{(y)}})} }\\ { a = z }\\ { b = a }\\ { c = b }\\ { \text{Solve for } d \text{ where} } \\ { d = c } \end{array} \right.$$

求解 y, t, z, a, b, c, d 的值

$$d=0$$