(1)a=(3/2,-√3/2) b=(1/2,√3/2)
a²=(3/2)²+(-√3/2)²=3 b²=(1/2)²+(√3/2)²=1
a•b=(3/2)(1/2)+(-√3/2)(√3/2)=0
因m⊥n,所以m•n=0
m•n=[a+(x²-3)b]•(-ya+xb)
=-ya²+x(x²-3)b²=-3y+x(x²-3)=0
所以y=x(x²-3)/3
即y=f(x)=(x³-3x)/3 所以 f'(x)=x²-1
令f'(x)
(1)a=(3/2,-√3/2) b=(1/2,√3/2)
a²=(3/2)²+(-√3/2)²=3 b²=(1/2)²+(√3/2)²=1
a•b=(3/2)(1/2)+(-√3/2)(√3/2)=0
因m⊥n,所以m•n=0
m•n=[a+(x²-3)b]•(-ya+xb)
=-ya²+x(x²-3)b²=-3y+x(x²-3)=0
所以y=x(x²-3)/3
即y=f(x)=(x³-3x)/3 所以 f'(x)=x²-1
令f'(x)