matlab中如何把符号多项式转换为数值多项式

Question

-(390625*xx*(xx - 1)*(xx + 1)*(xx - 1/5)*(xx + 1/5)*(xx - 2/5)*(xx + 2/5)*(xx - 3/5)*(xx + 3/5)*(xx - 4/5)*(xx + 4/5))/1768

是我求得的一个符号函数，如何把它转化为double类型，从而画出它的图像，（我试过str2double,但不成功），先谢谢各位

Answer 1

记该函数为f，用eval语句
完整代码如下

syms xx;
f=-(390625*xx*(xx - 1)*(xx + 1)*(xx - 1/5)*(xx + 1/5)*(xx - 2/5)*(xx + 2/5)*(xx - 3/5)*(xx + 3/5)*(xx - 4/5)*(xx + 4/5))/1768;
xx=-10:0.1:10;
plot(xx,eval(f));本回答被提问者采纳