Which of the following is equivalent to u⋅v\mathbf{u} \cdot \mathbf{v}u⋅v?
∑uivi\sum u_i v_i∑uivi
∣u∣∣v∣cos(θ)|\mathbf{u}||\mathbf{v}| \cos(\theta)∣u∣∣v∣cos(θ)
∣u∣∣v∣sin(θ)|\mathbf{u}||\mathbf{v}| \sin(\theta)∣u∣∣v∣sin(θ)
u2+v2\sqrt{u^2 + v^2}u2+v2