Question

Projection of a vector a on another vector b is given by -

• A.
• B.
• C.
• D. None of these

Answer 1

The correct option is B


We have seen that the projection of vector a on b will be a $cos\theta$ Let’s check the options and see which gives us a $cos\theta$
a.b=|a|b| $cos\theta$ ( We know that dot product of a & b is equal to a b $cos\theta$ )
So, it’s not correct.
Another option we have is -$\frac{a.b}{|b|}$
We know that \(a.b=|a||b|cos\theta\) so we’ll substitute this to the above expression - $\frac{|a||b|cos\theta }{|b|}=|a|cos\theta$
Which is what we wanted, so this option is correct.