Question

If $z_{1} = 2 + 5i,z_{2} = 3 - i$ then projection of $z_{1}$on $z_{2}$ is

• A. 1/10
• B. $1/\sqrt{10}$
• C. $- 7/10$
• D. None of these

Answer 1

Answer: (B)

$1/\sqrt{10}$

Answer 2

Sol. Projection of $z_{1}$on $z_{2}$ $= \frac{z_{1}oz_{2}}{|z_{2}|} = \frac{a_{1}a_{2} + b_{1}b_{2}}{\sqrt{a_{2}^{2} + b_{2}^{2}}} = \frac{1}{\sqrt{10}}.$