Mathematics · important
Condition for acute, obtuse, right angle for JEE
Scalar and vector products
Formula
\(\vec{a}\cdot\vec{b}>0\Rightarrow \theta<\dfrac{\pi}{2},\quad \vec{a}\cdot\vec{b}<0\Rightarrow \theta>\dfrac{\pi}{2},\quad \vec{a}\cdot\vec{b}=0\Rightarrow \theta=\dfrac{\pi}{2}\)
Variables: \(\theta\) is the angle between nonzero vectors \(\vec{a},\vec{b}\).
Conditions: \(\vec{a},\vec{b}\neq\vec{0}\).
Determining nature of angle using dot product sign.