{"id":5527,"date":"2021-09-16T20:28:21","date_gmt":"2021-09-16T14:58:21","guid":{"rendered":"https:\/\/mathemerize.com\/?p=5527"},"modified":"2021-11-22T17:34:06","modified_gmt":"2021-11-22T12:04:06","slug":"differentiation-of-cos-inverse-x","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/differentiation-of-cos-inverse-x\/","title":{"rendered":"Differentiation of cos inverse x"},"content":{"rendered":"
Here you will learn differentiation of cos inverse x or arccos x by using chain rule.<\/p>\n
Let’s begin –<\/p>\n
\nIf x \\(\\in\\) (-1, 1) , then the differentiation of \\(cos^{-1}x\\) with respect to x is \\(-1\\over \\sqrt{1 – x^2}\\).<\/p>\n
i.e. \\(d\\over dx\\) \\(cos^{-1}x\\) = \\(-1\\over \\sqrt{1 – x^2}\\) , for x \\(\\in\\) (-1, 1).<\/p>\n<\/blockquote>\n
Proof using chain rule :<\/h2>\n
\nLet y = \\(cos^{-1}x\\). Then,<\/p>\n
\\(cos(cos^{-1}x)\\) = x<\/p>\n
\\(\\implies\\) cos y = x<\/p>\n
Differentiating both sides with respect to x, we get<\/p>\n
\\(d\\over dx\\)(cos y) = \\(d\\over dx\\)(x)<\/p>\n
\\(d\\over dx\\) (cos y) = 1<\/p>\n
By chain rule,<\/p>\n
-sin y \\(dy\\over dx\\) = 1<\/p>\n
\\(dy\\over dx\\) = \\(-1\\over sin y\\)<\/p>\n
\\(dy\\over dx\\) = \\(-1\\over \\sqrt{1 – cos^2 y}\\)<\/p>\n
\\(\\implies\\) \\(dy\\over dx\\) = \\(-1\\over \\sqrt{1 – x^2}\\)<\/p>\n
\\(\\implies\\) \\(d\\over dx\\) \\(cos^{-1}x\\) = \\(-1\\over \\sqrt{1 – x^2}\\)\u00a0<\/p>\n
Hence, the differentiation of \\(cos^{-1}x\\) with respect to x is \\(-1\\over \\sqrt{1 – x^2}\\).<\/p>\n<\/blockquote>\n
Example<\/strong><\/span> : What is the differentiation of \\(cos^{-1} x^3\\) with respect to x ?<\/p>\n
Solution<\/strong><\/span> : Let y = \\(cos^{-1} x^3\\)<\/p>\n
Differentiating both sides with respect to x and using chain rule, we get<\/p>\n
\\(dy\\over dx\\) = \\(d\\over dx\\) (\\(cos^{-1} x^3\\))<\/p>\n
\\(dy\\over dx\\) = \\(-1\\over \\sqrt{1 – x^6}\\).\\(3x^2\\) = \\(-3x^2\\over \\sqrt{1 – x^6}\\)<\/p>\n
Hence, \\(d\\over dx\\) (\\(cos^{-1} x^3\\)) = \\(-3x^2\\over \\sqrt{1 – x^6}\\)<\/p>\n
Example<\/strong><\/span> : What is the differentiation of x + \\(cos^{-1} x\\) with respect to x ?<\/p>\n
Solution<\/strong><\/span> : Let y = x + \\(cos^{-1} x\\)<\/p>\n
Differentiating both sides with respect to x, we get<\/p>\n
\\(dy\\over dx\\) = \\(d\\over dx\\) (x) + \\(d\\over dx\\) (\\(cos^{-1} x\\))<\/p>\n
\\(dy\\over dx\\) = 1 + \\(-1\\over \\sqrt{1 – x^2}\\)<\/p>\n
Hence, \\(d\\over dx\\) (x + \\(cos^{-1} x\\)) = 1 – \\(1\\over \\sqrt{1 – x^2}\\)<\/p>\n
\nRelated Questions<\/h3>\n
What is the Differentiation of cos x ?<\/a><\/p>\n
What is the Integration of cos Inverse x ?<\/a><\/p>\n
What is the Differentiation of cosec inverse x ?<\/a><\/p>\n\n\n