6.1矢量线

这条线l1{"language":"en","fontFamily":"Times New Roman","fontSize":"18"}" class="Wirisformula" role="math" alt="L下标1" style="vertical-align:-12px;height:28px;width:14px">有方程

x-12=y+1-1=z-43{"language":"en","fontFamily":"Times New Roman","fontSize":"18"}" class="Wirisformula" role="math" alt="分子(x - 1)除以分母2端分数等于分子(y + 1)除以分母- 1端分数等于分子(z - 4)除以分母3端分数" style="vertical-align:-17px;height:47px;width:166px">

这条线l2{"language":"en","fontFamily":"Times New Roman","fontSize":"18"}" class="Wirisformula" role="math" alt="L下标2" style="vertical-align:-12px;height:28px;width:14px">有方程

r =i + 3k + t( i − j + 2k){"language":"en","fontFamily":"Times New Roman","fontSize":"18"}" class="Wirisformula" role="math" alt="加粗的r空格等于加粗的I空格加空格3加粗的k空格加空格t左括号加粗的I空格减去空格加粗的j空格加空格2加粗的k右括号" style="vertical-align:-6px;height:22px;width:207px">

在哪里t{"language":"en","fontFamily":"Times New Roman","fontSize":"18"}" class="Wirisformula" role="math" alt="t" style="vertical-align:-6px;height:22px;width:7px">是标量参数。