解答
x6−2x3+3=0
解答
x=63cos(3arctan(2))+63isin(3arctan(2)),x=63cos(3arctan(2)+2π)+63isin(3arctan(2)+2π),x=63cos(3arctan(2)+4π)+63isin(3arctan(2)+4π),x=63cos(3arctan(2))−63isin(3arctan(2)),x=63cos(3−arctan(2)+2π)+63isin(3−arctan(2)+2π),x=63cos(3−arctan(2)+4π)+63isin(3−arctan(2)+4π)
求解步骤
x6−2x3+3=0
用u=x3 和 u2=x6改写方程式u2−2u+3=0
解 u2−2u+3=0:u=1+2i,u=1−2i
u=1+2i,u=1−2i
代回 u=x3,求解 x
解 x3=1+2i:x=63cos(3arctan(2))+63isin(3arctan(2)),x=63cos(3arctan(2)+2π)+63isin(3arctan(2)+2π),x=63cos(3arctan(2)+4π)+63isin(3arctan(2)+4π)
解 x3=1−2i:x=63cos(3arctan(2))−63isin(3arctan(2)),x=63cos(3−arctan(2)+2π)+63isin(3−arctan(2)+2π),x=63cos(3−arctan(2)+4π)+63isin(3−arctan(2)+4π)
解为
x=63cos(3arctan(2))+63isin(3arctan(2)),x=63cos(3arctan(2)+2π)+63isin(3arctan(2)+2π),x=63cos(3arctan(2)+4π)+63isin(3arctan(2)+4π),x=63cos(3arctan(2))−63isin(3arctan(2)),x=63cos(3−arctan(2)+2π)+63isin(3−arctan(2)+2π),x=63cos(3−arctan(2)+4π)+63isin(3−arctan(2)+4π)