matlab定义符号函数如下,f1=0.1*x1-0.1/10000*x1^2-(0.05/10000)*(x1*x2);>> f1f1 =x1/10 - (5902958103587057*x1*x2)/1180591620717411303424 - x1^2/100000请问为什么?

Question

matlab定义符号函数如下,
f1=0.1*x1-0.1/10000*x1^2-(0.05/10000)*(x1*x2);
>> f1
f1 =
x1/10 - (5902958103587057*x1*x2)/1180591620717411303424 - x1^2/100000
请问为什么?

Answer 1

符号函数一般都会以最简整数比的形式显示,vpa()函数可以进行计算

>> syms x1 x2
>> f1=0.1*x1-0.1/10000*x1^2-(0.05/10000)*(x1*x2) 
f1 = 
x1/10 - (5902958103587057*x1*x2)/1180591620717411303424 - x1^2/100000
 
>> vpa(f1) 
ans = 
0.1*x1 - 0.0000050000000000000004090152695701565*x1*x2 - 0.00001*x1^2