Calculation: dFpz6P - 1

v  = 
- ω* x* sin( ω* t)
v = - ω* x* sin( ω* t)$$v$$ = $$-\omega\cdot x\cdot sin(\omega\cdot t)$$
v = - sin( t* ω)* x* ω$$v$$ = $$-sin(t\cdot \omega)\cdot x\cdot \omega$$