{"id":6108,"date":"2021-10-07T17:41:08","date_gmt":"2021-10-07T12:11:08","guid":{"rendered":"https:\/\/mathemerize.com\/?p=6108"},"modified":"2021-10-09T00:40:03","modified_gmt":"2021-10-08T19:10:03","slug":"equation-of-a-line-in-vector-form","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/equation-of-a-line-in-vector-form\/","title":{"rendered":"Equation of a Line in Vector Form"},"content":{"rendered":"
Here you will learn equation of a line in vector form passing through a fixed point and passing through two points.<\/p>\n
Let’s begin –<\/p>\n
The vector equation of a straight line passing through a fixed point with position vector \\(\\vec{a}\\) and parallel to a given vector \\(\\vec{b}\\) is <\/p>\n
\n\\(\\vec{r}\\) = \\(\\vec{a}\\) + \\(\\lambda \\vec{b}\\), where \\(\\lambda\\) is scalar.<\/p>\n<\/blockquote>\n
Note<\/b> : In the above equation \\(\\vec{r}\\) is the position vector of any point P (x, y, z) on the line. Therefore, \\(\\vec{r}\\) = \\(x\\hat{i} + y\\hat{j} + z\\hat{k}\\).<\/p>\n
Example<\/strong><\/span> : Find the vector equation of a line which passes through the point with position vector \\(2\\hat{i} – \\hat{j} + 4\\hat{k}\\) and is in the direction \\(\\hat{i} + \\hat{j} – 2\\hat{k}\\).<\/p>\n
Solution<\/span><\/strong> : Here \\(\\vec{a}\\) = \\(2\\hat{i} – \\hat{j} + 4\\hat{k}\\) and \\(\\vec{b}\\) = \\(\\hat{i} + \\hat{j} – 2\\hat{k}\\).<\/p>\n
So, the vector equation of the required line is<\/p>\n
\\(\\vec{r}\\) = \\(\\vec{a}\\) + \\(\\lambda \\vec{b}\\)<\/p>\n
or, \\(\\vec{r}\\) = (\\(2\\hat{i} – \\hat{j} + 4\\hat{k}\\)) + \\(\\lambda (\\hat{i} + \\hat{j} – 2\\hat{k})\\), where \\(\\lambda\\) is a scalar.<\/p>\n
Equation of Line in Vector Form Passing Through Two Points<\/strong><\/h4>\n
The vector equation of line passing through two points with position vectors \\(\\vec{a}\\) and \\(\\vec{b}\\) is<\/p>\n
\n\\(\\vec{r}\\) = \\(\\lambda\\) \\((\\vec{b} – \\vec{a})\\), where \\(\\lambda\\) is a scalar<\/p>\n<\/blockquote>\n
Example<\/strong><\/span> : Find the vector equation of a line which passes through the point A (3, 4, -7) and B (1, -1, 6)<\/p>\n
Solution<\/span><\/strong> : We know that the vector equation of line passing through two points with position vectors \\(\\vec{a}\\) and \\(\\vec{b}\\) is,<\/p>\n
\\(\\vec{r}\\) = \\(\\lambda\\) \\((\\vec{b} – \\vec{a})\\)<\/span><\/p>\n
Here \\(\\vec{a}\\) = \\(3\\hat{i} + 4\\hat{j} – 7\\hat{k}\\) and \\(\\vec{b}\\) = \\(\\hat{i} – \\hat{j} + 6\\hat{k}\\).<\/p>\n
So, the vector equation of the required line is<\/p>\n
\\(\\vec{r}\\) = (\\(3\\hat{i} + 4\\hat{j} – 7\\hat{k}\\)) + \\(\\lambda\\) (\\(\\hat{i} – \\hat{j} + 6\\hat{k}\\) – \\(3\\hat{i} + 4\\hat{j} – 7\\hat{k}\\))<\/p>\n
or, \\(\\vec{r}\\) = (\\(3\\hat{i} + 4\\hat{j} – 7\\hat{k}\\)) + \\(\\lambda\\) (\\(-2\\hat{i} – 5\\hat{j} + 13\\hat{k}\\))<\/p>\n
where \\(\\lambda\\) is a scalar.<\/p>\n\n\n