## Calculus 8th Edition

Let $\bf{C}$ be a smooth curve with position vector $r(t)$. The tangent vector is $r'(t)$.The unit tangent vector is: $$T(t)=\dfrac{r'(t)}{||r'(t)||}$$ Vector equation of tangent line at $t=a$ is: $s(u)=r(a)+u \cdot r'(a)$
Let $\bf{C}$ be a smooth curve with position vector $r(t)$. The tangent vector is $r'(t)$.The unit tangent vector is: $$T(t)=\dfrac{r'(t)}{||r'(t)||}$$ Vector equation of tangent line at $t=a$ is: $s(u)=r(a)+u \cdot r'(a)$