matlab 求-120*x^3-30*x^4+18*x^5+5*x^6-30*xy^2的极值syms x yf='-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^2fy =(-60)*x*y接下里roots怎么写呢?是:x0=roots([30,90
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![matlab 求-120*x^3-30*x^4+18*x^5+5*x^6-30*xy^2的极值syms x yf='-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^2fy =(-60)*x*y接下里roots怎么写呢?是:x0=roots([30,90](/uploads/image/z/1073299-67-9.jpg?t=matlab+%E6%B1%82-120%2Ax%5E3-30%2Ax%5E4%2B18%2Ax%5E5%2B5%2Ax%5E6-30%2Axy%5E2%E7%9A%84%E6%9E%81%E5%80%BCsyms+x+yf%3D%27-120%2Ax%5E3-30%2Ax%5E4%2B18%2Ax%5E5%2B5%2Ax%5E6-30%2Ax%2Ay%5E2%27%3Bfx%3Ddiff%28f%2Cx%29fy%3Ddiff%28f%2Cy%29%E7%BB%93%E6%9E%9C%E4%B8%BA%EF%BC%9Afx+%3D30%2Ax%5E5+%2B+90%2Ax%5E4+-+120%2Ax%5E3+-+360%2Ax%5E2+-+30%2Ay%5E2fy+%3D%28-60%29%2Ax%2Ay%E6%8E%A5%E4%B8%8B%E9%87%8Croots%E6%80%8E%E4%B9%88%E5%86%99%E5%91%A2%3F%E6%98%AF%EF%BC%9Ax0%3Droots%28%5B30%2C90)
matlab 求-120*x^3-30*x^4+18*x^5+5*x^6-30*xy^2的极值syms x yf='-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^2fy =(-60)*x*y接下里roots怎么写呢?是:x0=roots([30,90
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?
matlab 求-120*x^3-30*x^4+18*x^5+5*x^6-30*xy^2的极值syms x yf='-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^2fy =(-60)*x*y接下里roots怎么写呢?是:x0=roots([30,90
roots用来求多项式的根的,参数是多项式系数.
x0=roots([30,90,-120,-360,0,-30*y^2])
y0=roots([-60*x,0])