{"id":6516,"date":"2021-10-17T20:00:17","date_gmt":"2021-10-17T14:30:17","guid":{"rendered":"https:\/\/mathemerize.com\/?p=6516"},"modified":"2021-11-21T18:18:18","modified_gmt":"2021-11-21T12:48:18","slug":"how-to-find-the-conjugate-of-a-complex-number","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/how-to-find-the-conjugate-of-a-complex-number\/","title":{"rendered":"How to Find the Conjugate of a Complex Number"},"content":{"rendered":"
Here you will learn how to find the conjugate of a complex number and properties of conjugate with examples.<\/p>\n
Let’s begin –\u00a0<\/p>\n
Let z = a + ib be a complex number. Then the conjugate of z is denoted by \\(\\bar{z}\\) and is equal to a – ib.<\/p>\n
\nThus, z = a + ib \\(\\implies\\) \\(\\bar{z}\\) = a – ib<\/p>\n<\/blockquote>\n
It follows from this definition that the conjugate of a complex number is obtained by replacing i by -i.<\/p>\n
For Example<\/span><\/strong> : If z = 3 + 4i, then \\(\\bar{z}\\) = 3 – 4i.<\/p>\n
Properties of Conjugate<\/h3>\n
If \\(z\\), \\(z_1\\), \\(z_2\\) are complex numbers, then<\/p>\n
(i)<\/strong> \\(\\bar{\\bar{z}}\\) = z<\/p>\n
(ii)<\/strong> z + \\(\\bar{z}\\) = 2 Re (z)<\/p>\n
(iii)<\/strong> z – \\(\\bar{z}\\) = 2i Im (z)<\/p>\n
(iv)<\/strong> z = \\(\\bar{z}\\) \\(\\iff\\) z is purely real<\/p>\n
(v)<\/strong> z + \\(\\bar{z}\\) = 0 \\(\\implies\\) z is purely imaginary<\/p>\n
(vi)<\/strong> z\\(\\bar{z}\\) = \\([Re (z)]^2\\) + \\([Im (z)]^2\\)<\/p>\n
(vii)<\/strong> \\(\\bar{z_1 + z_2}\\) =\u00a0 \\(\\bar{z_1}\\) + \\(\\bar{z_2}\\)<\/p>\n
(viii)<\/strong> \\(\\bar{z_1 – z_2}\\) =\u00a0 \\(\\bar{z_1}\\) – \\(\\bar{z_2}\\)<\/p>\n
(ix)<\/strong> \\(\\bar{z_1z_2}\\) =\u00a0 \\(\\bar{z_1}\\) \\(\\bar{z_2}\\)<\/p>\n
(x)<\/strong> \\(\\bar{z_1\\over z_2}\\) =\u00a0 \\(\\bar{z_1}\\over \\bar{z_2}\\)<\/p>\n
Example<\/span><\/strong> : Multiply 3 – 2i by its conjugate.<\/p>\n
Solution<\/span><\/strong> : The conjugate of 3 – 2i is 3 + 2i.<\/p>\n
Hence, required product is = (3 – 2i)(3 + 2i) = \\(9 – 4i^2\\) = 9 + 4 = 13<\/p>\n
Example<\/span><\/strong> : Find the conjugate of \\(1\\over 3 + 4i\\).<\/p>\n
Solution<\/span><\/strong> : Let z = \\(1\\over 3 + 4i\\). Then,<\/p>\n
z = \\(1\\over 3 + 4i\\) \\(\\times\\) \\(3 – 4i\\over 3 – 4i\\) = \\(3 – 4i\\over 9 + 16\\) = \\({3\\over 25} – {4\\over 25}i\\)<\/p>\n
\\(\\therefore\\) Conjugate of z is \\(\\bar{z}\\) = \\({3\\over 25} – {4\\over 25}i\\).\u00a0<\/p>\n\n\n