Determine the unit tangent vector

[chwala]

Homework Statement

see attached

Relevant Equations

vector differentiation

I need a justification that $|\dfrac {dr}{dt}|$=$\dfrac {ds}{dt}$ cheers guys... all the other steps are easy and clear to me...

 

[PeroK]

Homework Statement:: see attached
Relevant Equations:: vector differentiation

View attachment 297138

I need a justification that [Modulus $\big | \dfrac {dr}{dt} \big |$=$\dfrac {ds}{dt}$] cheers guys... all the other steps are easy and clear to me...

We have $ds \equiv |d\vec r|$.

 

[chwala]

Aaaaah Perok cheers!

We have $ds \equiv |d\vec r|$.