{"id":3743,"date":"2021-08-08T06:37:02","date_gmt":"2021-08-08T06:37:02","guid":{"rendered":"https:\/\/mathemerize.com\/?p=3743"},"modified":"2021-11-30T19:35:03","modified_gmt":"2021-11-30T14:05:03","slug":"formula-and-graph-of-trigonometric-functions","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/formula-and-graph-of-trigonometric-functions\/","title":{"rendered":"Graph of Trigonometric Functions – Domain & Range"},"content":{"rendered":"
Here, you will learn graph of trigonometric functions and domain & range of trigonometric functions.<\/p>\n
y = sinx<\/b><\/p>\n <\/div>\n y = cosx<\/b><\/p>\n <\/div>\n <\/div> y = tanx<\/b><\/p>\n <\/div>\n y = cotx<\/b><\/p>\n <\/div>\n <\/div> y = secx<\/b><\/p>\n <\/div>\n y = cosecx<\/b><\/p>\n <\/div>\n <\/div> \n <\/p> <\/p>\n\n\n (i) sin\\(18^{\\circ}\\) = sin\\(\\pi\\over 10\\) = \\(\\sqrt{5}-1\\over 4\\) = cos\\(72^{\\circ}\\) = cos\\(2\\pi\\over 5\\)<\/p>\n (ii) cos\\(36^{\\circ}\\) = cos\\(\\pi\\over 5\\) = \\(\\sqrt{5}+1\\over 4\\) = sin\\(54^{\\circ}\\) = sin\\(3\\pi\\over 10\\)<\/p>\n (iii) sin\\(72^{\\circ}\\) = sin\\(2\\pi\\over 5\\) = \\(\\sqrt{10 + 2\\sqrt{5}}\\over 4\\) = cos\\(18^{\\circ}\\) = cos\\(\\pi\\over 10\\)<\/p>\n (iv) sin\\(36^{\\circ}\\) = sin\\(\\pi\\over 5\\) = \\(\\sqrt{10 – 2\\sqrt{5}}\\over 4\\) = cos\\(54^{\\circ}\\) = cos\\(3\\pi\\over 10\\)<\/p>\n (v) sin\\(15^{\\circ}\\) = sin\\(\\pi\\over 12\\) = \\(\\sqrt{3}-1\\over {2\\sqrt{2}}\\) = cos\\(75^{\\circ}\\) = cos\\(5\\pi\\over 12\\)<\/p>\n (vi) cos\\(15^{\\circ}\\) = sin\\(\\pi\\over 12\\) = \\(\\sqrt{3}+1\\over {2\\sqrt{2}}\\) = sin\\(75^{\\circ}\\) = sin\\(5\\pi\\over 12\\)<\/p>\n (vii) tan\\(15^{\\circ}\\) = tan\\(\\pi\\over 12\\) = \\(2 – \\sqrt{3}\\) = \\(\\sqrt{3}-1\\over {\\sqrt{3}+1}\\) = cot\\(75^{\\circ}\\) = cot\\(5\\pi\\over 12\\)<\/p>\n (viii) tan\\(75^{\\circ}\\) = tan\\(5\\pi\\over 12\\) = \\(2 + \\sqrt{3}\\) = \\(\\sqrt{3}+1\\over {\\sqrt{3}-1}\\) = cot\\(15^{\\circ}\\) = cot\\(\\pi\\over 12\\)<\/p>\n (ix) tan(\\(22.5^{\\circ}\\)) = tan\\(\\pi\\over 8\\) = \\(\\sqrt{2}-1\\) = cot(\\(67.5^{\\circ}\\)) = cot\\(3\\pi\\over 8\\)<\/p>\n (x) tan(\\(67.5^{\\circ}\\)) = tan\\(3\\pi\\over 8\\) = \\(\\sqrt{2}+1\\) = cot(\\(22.5^{\\circ}\\)) = cot\\(\\pi\\over 8\\)<\/p>\n\n\n Example : <\/span> Evaluate sin\\(78^{\\circ}\\) – sin\\(66^{\\circ}\\) – sin\\(42^{\\circ}\\) + sin\\(6^{\\circ}\\)<\/p>\n Solution : <\/span>(sin\\(78^{\\circ}\\) – sin\\(66^{\\circ}\\)) – (sin\\(42^{\\circ}\\) – sin\\(6^{\\circ}\\)-)
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\n\n\nValues of T-Ratio of some standard angles<\/h2>\n\n\n
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\n Angles
T-Ratio<\/td>\n 0<\/td>\n \\(\\pi\\over 6\\)<\/td>\n \\(\\pi\\over 4\\)<\/td>\n \\(\\pi\\over 3\\)<\/td>\n \\(\\pi\\over 2\\)<\/td>\n \\(\\pi\\)<\/td>\n <\/tr>\n \n \\(sin\\theta\\)<\/td>\n 0<\/td>\n \\(1\\over 2\\)<\/td>\n \\(1\\over \\sqrt{2}\\)<\/td>\n \\(\\sqrt{3}\\over 2\\)<\/td>\n 1<\/td>\n 0<\/td>\n <\/tr>\n \n \\(cos\\theta\\)<\/td>\n 1<\/td>\n \\(\\sqrt{3}\\over 2\\)<\/td>\n \\(1\\over \\sqrt{2}\\)<\/td>\n \\(1\\over 2\\)<\/td>\n 0<\/td>\n -1<\/td>\n <\/tr>\n \n \\(tan\\theta\\)<\/td>\n 0<\/td>\n \\(1\\over \\sqrt{3}\\)<\/td>\n 1<\/td>\n \\(\\sqrt{3}\\)<\/td>\n N.D<\/td>\n 0<\/td>\n <\/tr>\n \n \\(cot\\theta\\)<\/td>\n N.D<\/td>\n \\(\\sqrt{3}\\)<\/td>\n 1<\/td>\n \\(1\\over \\sqrt{3}\\)<\/td>\n 0<\/td>\n N.D<\/td>\n <\/tr>\n \n \\(sec\\theta\\)<\/td>\n 1<\/td>\n \\(2\\over \\sqrt{3}\\)<\/td>\n \\(\\sqrt{2}\\)<\/td>\n 2<\/td>\n N.D<\/td>\n -1<\/td>\n <\/tr>\n \n \\(cosec\\theta\\)<\/td>\n N.D<\/td>\n 2<\/td>\n \\(\\sqrt{2}\\)<\/td>\n \\(2\\over \\sqrt{3}\\)<\/td>\n 1<\/td>\n N.D<\/td>\n <\/tr>\n <\/tbody><\/table>
N.D = Not definedDomain, Ranges and Periodicity of Trigonometric function<\/h2>\n\n\n
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\n T-Ratio<\/td>\n Domain<\/td>\n Range<\/td>\n Period<\/td>\n <\/tr>\n \n sin x<\/td>\n R<\/td>\n [-1, 1]<\/td>\n \\(2\\pi\\)<\/td>\n <\/tr>\n \n cos x<\/td>\n R<\/td>\n [-1, 1]<\/td>\n \\(2\\pi\\)<\/td>\n <\/tr>\n \n tan x<\/td>\n R – {(2n+1)\\(\\pi\/2\\); n \\(\\in\\) I}<\/td>\n R<\/td>\n \\(\\pi\\)<\/td>\n <\/tr>\n \n cot x<\/td>\n R – {n\\(\\pi\\) : n \\(\\in\\) I}<\/td>\n R<\/td>\n \\(\\pi\\)<\/td>\n <\/tr>\n \n sec x<\/td>\n R – {(2n+1)\\(\\pi\/2\\); n \\(\\in\\) I}<\/td>\n (-\\(\\infty\\), -1] \\(\\cup\\) [1, \\(\\infty\\)]<\/td>\n \\(2\\pi\\)<\/td>\n <\/tr>\n \n cosec x<\/td>\n R – {n\\(\\pi\\) : n \\(\\in\\) I}<\/td>\n (-\\(\\infty\\), -1] \\(\\cup\\) [1, \\(\\infty\\)]<\/td>\n \\(2\\pi\\)<\/td>\n <\/tr>\n <\/tbody><\/table>
\n\n\nTrigonometric ratios of some standard angles :<\/h2>\n
\n = 2cos(\\(60^{\\circ}\\))sin(\\(18^{\\circ}\\)) – 2cos(\\(36^{\\circ}\\))sin(\\(30^{\\circ}\\))
\n = sin\\(18^{\\circ}\\) – cos\\(36^{\\circ}\\)
\n = (\\(\\sqrt{5}-1\\over 4\\)) – (\\(\\sqrt{5}+1\\over 4\\)) = \\(-1\\over 2\\)
<\/p>\n\n\n\n