y =
(-1/2-1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2+(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)+(-1/2+1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2-(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)-(-1/2+1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2+(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)-(-1/2-1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2-(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)

要对y求积分， 对这个式子在0～x(未知具体数)之间求积分，最后给出的结果是
int((-1/2-1/2*i*3^(1/2))*(-8/27-16/75*exp((1/100*t-9/50)*(t-18))^2+2/3*(1-4/25*t)^2+(1/4*(16/27+32/75*exp((1/100*t-9/50)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp((1/100*t-9/50)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)+(-1/2+1/2*i*3^(1/2))*(-8/27-16/75*exp((1/100*t-9/50)*(t-18))^2+2/3*(1-4/25*t)^2-(1/4*(16/27+32/75*exp((1/100*t-9/50)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp((1/100*t-9/50)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)-(-1/2+1/2*i*3^(1/2))*(-8/27-16/75*exp((1/100*t-9/50)*(t-18))^2+2/3*(1-4/25*t)^2+(1/4*(16/27+32/75*exp((1/100*t-9/50)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp((1/100*t-9/50)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)-(-1/2-1/2*i*3^(1/2))*(-8/27-16/75*exp((1/100*t-9/50)*(t-18))^2+2/3*(1-4/25*t)^2-(1/4*(16/27+32/75*exp((1/100*t-9/50)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp((1/100*t-9/50)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3),t = 0 .. x)

等于又把我输的命令打了一遍。
我想要解出最后表达式

谢谢大家了，麻烦你们了

对t进行积分吗?参考如下:
syms x t;
y=(-1/2-1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2+(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)+(-1/2+1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2-(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)-(-1/2+1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2+(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3)-(-1/2-1/2*i*3^(1/2))*(-8/27-16/75*exp(-1/100*(-t+18)*(t-18))^2+2/3*(1-4/25*t)^2-(1/4*(16/27+32/75*exp(-1/100*(-t+18)*(t-18))^2-4/3*(1-4/25*t)^2)^2+1/27*(-16/25*exp(-1/100*(-t+18)*(t-18))^2-(1-4/25*t)^2-4/3)^3)^(1/2))^(1/3);
y的积分为(对t积):int(y,t,0,x)

不知道是不是你想要的答案??

谢谢你，是这样的，我输入int（y,t,0,x）这个命令以后呢，给出的结果还是
int（y的表达式,t,0,x）;我想要的是它求出来的结果。

没遇到过这种情况,不清楚了,呵呵

int函数用以演算一函数的积分项， 这个函数要找出一符号式 F 使得diff(F)=f。如果积分式的解析式 (analytical form, closed form) 不存在的话或是MATLAB无法找到，则 int 传回原输入的符号式。

谢谢你了，明白了