matlab 解2元方程

直接用solve解不行，先进行整合。
f1='1/6+(5/6)/(1+exp(1.702*xy))-1/2'%把x*y当成一个变量
xy=solve(f1)%求解xy的值
f2='1/6+(5/6)/(1+exp(-1.702*x+1.702*xy))-1'%展开
f3=subs(f2,'xy',xy)%把xy的值代f2
x=solve(f3)%求解x
f4='1/6+(5/6)/(1+exp(1.702*x*y))-1/2'%再拆开xy
f5=subs(f4,'x',x)%代入x
y=solve(f5)%求解y

运行结果：
f1 =1/6+(5/6)/(1+exp(1.702*xy))-1/2
xy =.23822861815990856755464930403311
f2 =1/6+(5/6)/(1+exp(-1.702*x+1.702*xy))-1
f3 =-5/6+5/6/(1+exp(-1.702*x+.40546510810816438197801311546435))

x =185.69932338571710748362082828445

f4 =1/6+(5/6)/(1+exp(1.702*x*y))-1/2
f5 =-1/3+5/6/(1+exp(316.06024840249051693712264974013*y))

y =.12828728388260336678414831727309e-2

验证答案：
>> 1/6+(5/6)/(1+exp(1.702*x*y))

ans =

.50000000000000000000000000000000

>> 1/6+(5/6)/(1+exp(-1.702*x*(1-y)))

ans =

1.00000000000000000