$|\vec{a}|=5,|\vec{b}|=10$-and angle between $\vec{a}$ and $\vec{b}$ is $60^{\circ}$, then $|\overri

Question

$|\vec{a}|=5,|\vec{b}|=10$-and angle between $\vec{a}$ and $\vec{b}$ is $60^{\circ}$, then $|\overrightarrow{\mathrm{a}}+\overrightarrow{\mathrm{b}}|$-is

Professor PC Thomas Classes · Answer

$|\vec{a}+\vec{b}| = \sqrt{a^2+b^2+2ab\cos	heta} = \sqrt{5^2+10^2+2(5)(10)\cos 60^{\circ}} = \sqrt{175} = 5\sqrt{7}$.