matlab 求-120*x^3-30*x^4+18*x^5+5*x^6-30*xy^2的极值
matlab 求-120*x^3-30*x^4+18*x^5+5*x^6-30*xy^2的极值
syms x y
f='-120*x^3-30*x^4+18*x^5+5*x^6-30*x*y^2';
fx=diff(f,x)
fy=diff(f,y)
结果为:
fx =
30*x^5 + 90*x^4 - 120*x^3 - 360*x^2 - 30*y^2
fy =
(-60)*x*y
接下里roots怎么写呢?
是:
x0=roots([30,90,-120,-360,0,-30*y^2])
y0=roots([0,0,0,0,-60,-60*x,0])
还是怎么写呢?