1.b=(m,n)
a*b=lal*lbl*cos=√5*3√5*(-1)=m-2n=-15
m^2+n^2=45得b=(-3,6)
2.原式=6e1*e1-e1*e2-2e2*e2=6-2-le1l*le2l*cos=4-1/2=7/2
3.(λa+b)*a=(λ+4,-3λ-2)*(1,-3)=λ+4+9λ+6=0
λ=-1
1.b=(m,n)
a*b=lal*lbl*cos=√5*3√5*(-1)=m-2n=-15
m^2+n^2=45得b=(-3,6)
2.原式=6e1*e1-e1*e2-2e2*e2=6-2-le1l*le2l*cos=4-1/2=7/2
3.(λa+b)*a=(λ+4,-3λ-2)*(1,-3)=λ+4+9λ+6=0
λ=-1