{"id":6110,"date":"2021-10-07T17:43:47","date_gmt":"2021-10-07T12:13:47","guid":{"rendered":"https:\/\/mathemerize.com\/?p=6110"},"modified":"2021-10-09T00:40:35","modified_gmt":"2021-10-08T19:10:35","slug":"cartesian-equation-of-a-line","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/cartesian-equation-of-a-line\/","title":{"rendered":"Cartesian Equation of a Line"},"content":{"rendered":"
Here you will learn cartesian equation of line in 3d passing through a fixed point and passing through two points.<\/p>\n
Let’s begin –<\/p>\n
The cartesian equations of a straight line passing through a fixed point \\((x_1, y_1, z_1)\\) having direction ratios proportional to a, b, c is given by<\/p>\n
\n\\(x – x_1\\over a\\) = \\(y – y_1\\over b\\) = \\(z – z_1\\over c\\)<\/p>\n<\/blockquote>\n
Remark 1<\/strong> : The above form of a line is known as the symmetrical form of a line.<\/p>\n
Remark 2<\/strong> : The parametric equations of the line \\(x – x_1\\over a\\) = \\(y – y_1\\over b\\) = \\(z – z_1\\over c\\) are<\/p>\n
\nx = \\(x_1 + a\\lambda\\), y = \\(y_1 + b\\lambda\\), z = \\(z_1 + c\\lambda\\), where \\(\\lambda\\) is the parameter.<\/p>\n<\/blockquote>\n
Remark 3<\/strong> : The coordinates of any point on the line \\(x – x_1\\over a\\) = \\(y – y_1\\over b\\) = \\(z – z_1\\over c\\) are<\/p>\n
\n(\\(x_1 + a\\lambda\\), \\(y_1 + b\\lambda\\), \\(z_1 + c\\lambda\\)), where \\(\\lambda\\) \\(\\in\\) R.<\/p>\n<\/blockquote>\n
Remark 4<\/strong> : Since the direction cosines of a line are also its direcion ratios. Therefore, equations of a line passing through \\((x_1, y_1, z_1)\\) and having direction cosines l, m, n are<\/p>\n
\n\\(x – x_1\\over l\\) = \\(y – y_1\\over m\\) = \\(z – z_1\\over n\\)<\/p>\n<\/blockquote>\n
Remark 5<\/strong> : Since x, y and z-axes passes through the origin and have direction cosines 1, 0, 0; 0, 1, 0 and 0, 0, 1 respectively. Therefore, their equations are<\/p>\n
\nx-axis : \\(x – 0\\over 1\\) = \\(y – 0\\over 0\\) = \\(z – 0\\over 0\\) or, y = 0 and z = 0<\/p>\n
y-axis : \\(x – 0\\over 0\\) = \\(y – 0\\over 1\\) = \\(z – 0\\over 0\\) or, x = 0 and z = 0<\/p>\n
z-axis : \\(x – 0\\over 0\\) = \\(y – 0\\over 0\\) = \\(z – 0\\over 1\\) or, y = 0 and y = 0<\/p>\n<\/blockquote>\n
Cartesian Equation of a Line Passing Through Two Points<\/strong><\/h4>\n
The Cartesian equation of aline passing through two given points \\((x_1, y_1, z_1)\\) and \\((x_2, y_2, z_2)\\) is given by<\/p>\n
\n\\(x – x_1\\over x_2 – x_1\\) = \\(y – y_1\\over y_2 – y_1\\) = \\(z – z_1\\over z – z_1\\)<\/p>\n<\/blockquote>\n
Example<\/span><\/strong> : Find the cartesian equation of line passing through A(3, 4, -7) and B(1, -1, 6).<\/p>\n
Solution<\/strong><\/span> : We have, A(3, 4, -7) and B(1, -1, 6)<\/p>\n
The cartesian equation of line passing through two points is<\/p>\n
\\(x – x_1\\over x_2 – x_1\\) = \\(y – y_1\\over y_2 – y_1\\) = \\(z – z_1\\over z – z_1\\)<\/p>\n
= \\(x – 3\\over -2\\) = \\(y – 4\\over -5\\) = \\(z + 7\\over 13\\)<\/p>\n\n\n