Question

已知向量a的模为1,向量b的模为5,向量a点乘向量b=4 求[(向量a+向量b)X(向量a-向量b)]^2

Answer 1

[（ a+b)*(a-b)]^2

=(a^2-b^2)^2

=(1-25)^2

=24^2

=576