matlab - Matlab wont shorten answer after format short

Question

I'm trying to get matlab to shorten the answer into scientific notation but it continues to display long numbers.

Here is my matlab script:

syms E;
kb=8.617e-5; %eV/k
h=4.136e-15; %eV*s
Ts=5760; %k
q=1; %ev
c=3.0e8; %m/s
theta_s=atan(7e8/1.5e11); %rad

format short
Il_per_area = (q*pi/2)*(1-cos(2*theta_s))*int(((2/h^3*c^2)*E^2)/(exp(E/(kb*Ts-1))),E)

This is the result matlab gave me:

Il_per_area =

(52508430427297951419542428146127404493579145286547868195529063488882991519987*exp((2251799813685248*E)/1134143295600563)*((5070602400912917605986812821504*E^2)/1286281014955706024710845916969 - (4503599627370496*E)/1134143295600563 + 2))/2361183241434822606848

Can someone help me.

Answer 1

这就是 Matlab 处理符号表达式的方式。您可以尝试替换 E 的值

subs(Il_per_area, 3.2)

或者更确切地说，您希望在带有符号 E 的答案中看到较短的参数：

添加一行可变精度算术 (VPA)

vpa(Il_per_area,4)

答案是

ans =

2.223e55*exp(1.985*E)*(3.942*E^2 - 3.971*E + 2.0)