matlab解[x,y]=solve('31200*(1691-y)/1691=-8.314*y*log(x)','58160*(1563-y)/1563=-8.314*y*log(1-x)')为什么会是x=z1y=-31200.0/(8.314*log(z1)-18.450620934358367829686575990538)

Question

matlab解[x,y]=solve('31200*(1691-y)/1691=-8.314*y*log(x)','58160*(1563-y)/1563=-8.314*y*log(1-x)')
为什么会是
x =
z1
y =
-31200.0/(8.314*log(z1) - 18.450620934358367829686575990538)

Answer 1

用solve求解确实是这样的,应该用fsolve求解.结果为
ans =
[ 0.54592788329153985049657649142318, 1328.630754883516146946931257844]
function f=fx(x)
f(1)=31200*(1691-x(2))/1691+8.314*x(2)*log(x(1));
f(2)=58160*(1563-x(2))/1563+8.314*x(2)*log(1-x(1));
>>[x,f,h]=fsolve(@fx,[0.01,1000])
x =
1.0e+003 *
0.0005 1.3286
f =
1.0e-010 *
-0.1455 0.1637
h =
1
>>vpa(x)
ans =
[ 0.54592788329153985049657649142318, 1328.630754883516146946931257844]