Question

问一道向量a向量=-e1向量+3*e2向量,b向量=4*e1向量+2*e2向量,c向量=-3*e1向量+12*e2向量,

Answer 1

由b=4e1+2e2,c=-3e1+12e2可得

e1=(6b-c)/27,e2=（3b+4c)/54

∴a=-e1+3e2=-(6b-c)/27+（3b+4c)/18

=7c/27-b/18