{"id":5824,"date":"2021-10-03T17:52:23","date_gmt":"2021-10-03T12:22:23","guid":{"rendered":"https:\/\/mathemerize.com\/?p=5824"},"modified":"2021-11-26T00:00:09","modified_gmt":"2021-11-25T18:30:09","slug":"integration-of-tanx","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/integration-of-tanx\/","title":{"rendered":"Integration of Tanx"},"content":{"rendered":"
Here you will learn proof of integration of tanx or tan x and examples based on it.<\/p>\n
Let’s begin –<\/p>\n
\nThe integration of tanx is – log |cos x| + C<\/strong> or log |sec x| + C<\/strong><\/p>\n
i.e. \\(\\int\\) (tanx) dx = – log |cos x| + C or,<\/p>\n
\\(\\int\\) (tanx) dx = log |sec x| + C<\/p>\n<\/blockquote>\n
Proof :\u00a0\u00a0<\/strong><\/p>\n
\nLet I = \\(\\int\\) (tan x) dx<\/p>\n
Then, I = \\(\\int\\) \\(sin x\\over cos x\\) dx<\/p>\n
Let cos x = t\u00a0<\/p>\n
Then, d(cos x) = dt \\(\\implies\\) -sin x dx = dt\u00a0<\/p>\n
\\(\\implies\\) dx = \\(-dt\\over sin x\\)<\/p>\n
Putting cos x = t, and dx = \\(-dt\\over sin x\\), we get<\/p>\n
I = \\(\\int\\) \\(sin x\\over cos x\\) \\(\\times\\) \\(-dt\\over sin x\\)<\/p>\n
= \\(\\int\\) \\(-1\\over t\\) dt = – log |t| + C<\/p>\n
= – log |cos x| + C<\/p>\n
And cos x = \\(1\\over sec x\\)<\/p>\n
\\(\\implies\\) I = -log |1\/sec x| + C = -\\(log |sec^{-1} x|\\) + C = log |sec x| + C<\/p>\n
Hence, \\(\\int\\) (tanx) dx = – log |cos x| + C or, \\(\\int\\) (tanx) dx = log |sec x| + C<\/p>\n<\/blockquote>\n
Example<\/span><\/strong> : Evaluate : \\(\\int\\)\u00a0\\(\\sqrt{{1-cos 2x}\\over {1+cos 2x}}\\) dx<\/p>\n
Solution<\/span><\/strong> : We have,\u00a0<\/p>\n
I = \\(\\int\\) \\(\\sqrt{{1-cos 2x}\\over {1+cos 2x}}\\) dx<\/p>\n
By Trigonometry formulas,<\/p>\n
1 – cos 2x = \\(2sin^2 x\\) and 1 + cos 2x = \\(2cos^2 x\\)<\/p>\n
\\(\\implies\\) I = \\(\\int\\) \\(\\sqrt{{2sin^2 x}\\over {2cos^2 x}}\\) dx<\/p>\n
\\(\\implies\\) I = \\(\\int\\) \\({sin x}\\over {cos x}\\) dx<\/p>\n
{\\(\\because\\) \\({sin x}\\over {cos x}\\) = tan x }<\/p>\n
\\(\\implies\\) I = \\(\\int\\) tan x dx\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0<\/p>\n
\\(\\implies\\) I = log |sec x| + C = – log |cos x| + C<\/p>\n
\nRelated Questions<\/h3>\n
What is the Differentiation of tan x ?<\/a><\/p>\n
What is the Integration of tan inverse x ?<\/a><\/p>\n
What is the Differentiation of tan inverse x ?<\/a><\/p>\n\n\n