Use the dot product to find the magnitude of u. $\mathbf { u } = 35 \mathbf { i } + 40 \mathbf { j }$
A)40
B) $\sqrt { 2829 }$
C) $\sqrt { 2823 }$
D) $5 \sqrt { 113 }$
E)35

Question

Use the dot product to find the magnitude of u.  $\mathbf { u } = 35 \mathbf { i } + 40 \mathbf { j }$  
A)40
B) $\sqrt { 2829 }$
C) $\sqrt { 2823 }$
D) $5 \sqrt { 113 }$
E)35

Quizplus · Accepted Answer

The magnitude of a vector $\mathbf{u} = a\mathbf{i} + b\mathbf{j}$ is given by $\sqrt{a^2 + b^2}$. For $\mathbf{u} = 35\mathbf{i} + 40\mathbf{j}$, the magnitude is $\sqrt{35^2 + 40^2} = \sqrt{1225 + 1600} = \sqrt{2825} = 5\sqrt{113}$.

Use the Dot Product to Find the Magnitude of U u=35i+40j\mathbf { u } = 35 \mathbf { i } + 40 \mathbf { j }u=35i+40j

Use the Dot Product to Find the Magnitude of U $\mathbf { u } = 35 \mathbf { i } + 40 \mathbf { j }$