{"id":6505,"date":"2021-10-17T15:10:45","date_gmt":"2021-10-17T09:40:45","guid":{"rendered":"https:\/\/mathemerize.com\/?p=6505"},"modified":"2021-11-21T18:29:36","modified_gmt":"2021-11-21T12:59:36","slug":"integral-powers-of-iota-complex-numbers","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/integral-powers-of-iota-complex-numbers\/","title":{"rendered":"Integral Powers of Iota – Complex Numbers"},"content":{"rendered":"
Here you will learn complex number i (iota) and integral powers of iota with examples.<\/p>\n
Let’s begin –<\/p>\n
Positive Integral Powers of iota(i) :<\/strong><\/p>\n We have,<\/p>\n i = \\(\\sqrt{-1}\\)<\/p>\n \\(\\therefore\\) \\(i^2\\) = -1<\/p>\n \\(i^3\\) = \\(i^2\\) \\(\\times\\) i = -i<\/p>\n \\(i^4\\) = \\((i^2)^2\\) = \\((-1)^2\\) = 1<\/p>\n<\/blockquote>\n In order to compute \\(i^n\\) for n > 4, we divide n by 4 and obtain the remainder r. Let m be the quotient when n is divided by 4. Then,<\/p>\n n = 4m + r, where 0 \\(\\le\\) r < 4<\/p>\n \\(\\implies\\) \\(i^n\\) = \\(i^{4m + r}\\) = \\((i^4)^m i^r\\) = \\(i^4\\)<\/p>\n<\/blockquote>\n Thus, the value of \\(i^n\\) for n > 4 is \\(i^r\\), where r is the remainder when n is divide by 4.<\/p>\n Negative integral powers of iota(i) :<\/strong><\/p>\n By the law of indices, we have<\/p>\n \\(i^{-1}\\) = \\(1\\over i\\) = \\(i^3\\over i^4\\) = \\(i^3\\) = -i<\/p>\n \\(i^{-2}\\) = \\(1\\over i^2\\) = \\(1\\over -1\\) = -1<\/p>\n \\(i^{-3}\\) = \\(1\\over i^3\\) = \\(1\\over i^4\\) = i<\/p>\n \\(i^{-4}\\) = \\(1\\over i^4\\) = \\(1\\over 1\\) = 1<\/p>\n<\/blockquote>\n If n > 4, then<\/p>\n \\(i^{-n}\\) = \\(1\\over i^n\\) = \\(1\\over i^r\\), where r is the remainder when n is divided by 4.<\/p>\n<\/blockquote>\n Note<\/strong> : \\(i^{0}\\) is defined as 1.<\/p>\n Example<\/span><\/strong> : Evaluate the following :<\/p>\n (i) \\(i^{135}\\) <\/p>\n (ii) \\(i^{19}\\)<\/p>\n (iii) \\(i^{-999}\\)<\/p>\n Solution<\/span><\/strong> : <\/p>\n (i) 135 leaves remainder as 3 when it is divided by 4.<\/p>\n \\(\\therefore\\) \\(i^{135}\\) = \\(i^3\\) = -i<\/p>\n (ii) The remainder is when 19 is divided by 4.<\/p>\n \\(\\therefore\\) \\(i^{19}\\) = \\(i^3\\) = -i<\/p>\n (iii) We have, \\(i^{-999}\\) = \\(1\\over i^{999}\\)<\/p>\n On dividing 999 by 4, we obtain 3 as the remainder.<\/p>\n \\(\\therefore\\) \\(i^{999}\\) = \\(i^3\\)<\/p>\n \\(\\implies\\) \\(i^{-999}\\) = \\(1\\over i^{999}\\) = \\(1\\over i^3\\) = \\(i\\over i^4\\) = \\(i\\over 1\\) = i<\/p>\n\n\n\n
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