Question: where is the universal joint on a truck

title: Universal joint
text: x ^ 2 = ( − cos ⁡ β sin ⁡ γ 2 , cos ⁡ γ 2 , sin ⁡ β sin ⁡ γ 2 ) ( \ displaystyle ( \ hat ( \ mathbf ( x ) ) ) _ ( 2 ) = ( - \ cos \ beta \ sin \ gamma _ ( 2 ) \ , , \ , \ cos \ gamma _ ( 2 ) \ , , \ , \ sin \ beta \ sin \ gamma _ ( 2 ) ) )