Asosiy tarkibga o'tish

12.8-bo'lim : Tangent, normal va binormal vektorlar

2. : \(\vec r\left( t \right) = t{{\bf{e}}^{2t}}\,\vec i + \left( {2 - {t^2}} \right)\vec j - {{\bf{e}}^{2t}}\vec k\) vektor funksiyasi uchun birlik tangens vektorini toping

Yechim

Ushbu bo'limdagi eslatmalardan bilamizki, birlik tangens vektorini olish uchun bizga faqat vektor funksiyasining hosilasi va uning kattaligi kerak bo'ladi. Mana bu miqdorlar.

\[\vec r'\left( t \right) = \left( {{{\bf{e}}^{2t}} + 2t{{\bf{e}}^{2t}}} \right)\,\vec i - 2t\,\vec j - 2{{\bf{e}}^{2t}}\vec k\] \[\left\| {\vec r'\left( t \right)} \right\| = \sqrt {{{\left( {{{\bf{e}}^{2t}} + 2t{{\bf{e}}^{2t}}} \right)}^2} + {{\left( { - 2t} \right)}^2} + {{\left( { - 2{{\bf{e}}^{2t}}} \right)}^2}} = \sqrt {{{\left( {{{\bf{e}}^{2t}} + 2t{{\bf{e}}^{2t}}} \right)}^2} + 4{t^2} + 4{{\bf{e}}^{4t}}} \]
2-qadam

Bu vektor funksiyasi uchun birlik tangens vektori quyidagicha:

\[\require{bbox} \bbox[2pt,border:1px solid black]{{\vec T\left( t \right) = \frac{1}{{\sqrt {{{\left( {{{\bf{e}}^{2t}} + 2t{{\bf{e}}^{2t}}} \right)}^2} + 4{t^2} + 4{{\bf{e}}^{4t}}} }}\left( {\left( {{{\bf{e}}^{2t}} + 2t{{\bf{e}}^{2t}}} \right)\,\vec i - 2t\,\vec j - 2{{\bf{e}}^{2t}}\vec k} \right)}}\]

E'tibor bering, bu bilan bog'liq "chalkashlik" tufayli biz har bir atama uchun kattalikni taqsimlamadik, chunki biz odatdagidek. Bu muammo ular qanchalik "tartibsiz" bo'lishi mumkinligiga yaxshi misoldir.