\(\overline{O A}=2 \hat{i}+2 \hat{j}\)
\(|\overline{O A}|=\sqrt{4+4} \Rightarrow 2 \sqrt{2}\)
On rotating by an angle of \(45^{\circ}\) anticlockwise it will lie along \(y\)-axis.
So \(\vec{A}=2 \sqrt{2} \hat{j}\)
$(a)$ $\vec{a}+\vec{b}$
$(b)$ $3 a_x+2 b_y$
$(c)$ $(\vec{a}+\vec{b}-\vec{c})$