Question

matlab写公式五元二次方程组用matlab能写出来吗?请给个例子

Answer 1

给个例子,注意并不是所有的五元二次方程组都有解.

syms x y z s t

f1=x+y-z+s+t;

f2=x^2-y^2+2*z;

f3=x*y+s*t;

f4=z-s*t;

f5=x^2+y^2-2*t;

[x,y,z,s,t]=solve(f1,f2,f3,f4,f5);

解得：

x =

0

1/2*2^(1/2)

1/2*2^(1/2)

-1/2*2^(1/2)

-1/2*2^(1/2)

y =

0

1+(-2-2*2^(1/2))^(1/2)

1-(-2-2*2^(1/2))^(1/2)

1+(-2+2*2^(1/2))^(1/2)

1-(-2+2*2^(1/2))^(1/2)

z =

0

-(2^(1/2)-1)*(1+(-2-2*2^(1/2))^(1/2))/(1/2*2^(1/2)*(1+(-2-2*2^(1/2))^(1/2))-1/2*2^(1/2)-1-(-2-2*2^(1/2))^(1/2))

-(2^(1/2)-1)*(1-(-2-2*2^(1/2))^(1/2))/(1/2*2^(1/2)*(1-(-2-2*2^(1/2))^(1/2))-1/2*2^(1/2)-1+(-2-2*2^(1/2))^(1/2))

-(-1-2^(1/2))*(1+(-2+2*2^(1/2))^(1/2))/(-1/2*2^(1/2)*(1+(-2+2*2^(1/2))^(1/2))+1/2*2^(1/2)-1-(-2+2*2^(1/2))^(1/2))

-(-1-2^(1/2))*(1-(-2+2*2^(1/2))^(1/2))/(-1/2*2^(1/2)*(1-(-2+2*2^(1/2))^(1/2))+1/2*2^(1/2)-1+(-2+2*2^(1/2))^(1/2))

s =

0

1/(1/2*2^(1/2)*(1+(-2-2*2^(1/2))^(1/2))-1/2*2^(1/2)-1-(-2-2*2^(1/2))^(1/2))*(1+(-2-2*2^(1/2))^(1/2))

1/(1/2*2^(1/2)*(1-(-2-2*2^(1/2))^(1/2))-1/2*2^(1/2)-1+(-2-2*2^(1/2))^(1/2))*(1-(-2-2*2^(1/2))^(1/2))

1/(-1/2*2^(1/2)*(1+(-2+2*2^(1/2))^(1/2))+1/2*2^(1/2)-1-(-2+2*2^(1/2))^(1/2))*(1+(-2+2*2^(1/2))^(1/2))

1/(-1/2*2^(1/2)*(1-(-2+2*2^(1/2))^(1/2))+1/2*2^(1/2)-1+(-2+2*2^(1/2))^(1/2))*(1-(-2+2*2^(1/2))^(1/2))

t =

0

1/2*2^(1/2)*(1+(-2-2*2^(1/2))^(1/2))

1/2*2^(1/2)*(1-(-2-2*2^(1/2))^(1/2))

-1/2*2^(1/2)*(1+(-2+2*2^(1/2))^(1/2))

-1/2*2^(1/2)*(1-(-2+2*2^(1/2))^(1/2))