AIEEE 2005 (Offline)Question 1
For any vector $\vec a$, the value of $\left(\vec a\times\hat i\right)^{2}+\left(\vec a\times\hat j\right)^{2}+\left(\vec a\times\hat k\right)^{2}$ is equal to :
Vector Algebra
Solution
$|\vec a\times\hat i|^2=a^2-a_1^2$, etc.; summing gives $3a^2-a^2=2a^2$.