{"id":899,"date":"2023-05-05T10:00:42","date_gmt":"2023-05-05T04:30:42","guid":{"rendered":"https:\/\/www.aplustopper.com\/?p=899"},"modified":"2023-05-06T09:19:01","modified_gmt":"2023-05-06T03:49:01","slug":"trigonometry-for-specific-angles","status":"publish","type":"post","link":"https:\/\/www.aplustopper.com\/trigonometry-for-specific-angles\/","title":{"rendered":"Trigonometric Ratios Of Some Specific Angles"},"content":{"rendered":"

Trigonometric Ratios Of Some Specific Angles<\/strong><\/h2>\n

The angles 0\u00b0, 30\u00b0, 45\u00b0, 60\u00b0, 90\u00b0 are angles for which we have values of T.R.<\/p>\n\n\n\n\n\n\n\n\n\n
\n

\u03b8<\/strong><\/p>\n<\/td>\n

0\u00b0<\/strong><\/td>\n30\u00b0<\/strong><\/td>\n45\u00b0<\/strong><\/td>\n60\u00b0<\/strong><\/td>\n90\u00b0<\/strong><\/td>\n<\/tr>\n
\n

Sin<\/strong><\/p>\n<\/td>\n

0<\/td>\n1\/2<\/td>\n1\/\u221a2<\/td>\n\u00a0\u221a3\/2<\/td>\n\n

1<\/p>\n<\/td>\n<\/tr>\n

\n

Cos<\/strong><\/p>\n<\/td>\n

1<\/td>\n\u00a0\u221a3\/2<\/td>\n\u00a01\/\u221a2<\/td>\n1\/2<\/td>\n0<\/td>\n<\/tr>\n
\n

Tan<\/strong><\/p>\n<\/td>\n

0<\/td>\n\u00a01\/\u221a3<\/td>\n1<\/td>\n\u221a3<\/td>\n\u221e<\/td>\n<\/tr>\n
Cosec<\/strong><\/td>\n\u221e<\/td>\n2<\/td>\n\u221a2<\/td>\n2\/\u221a3<\/td>\n\n

1<\/p>\n<\/td>\n<\/tr>\n

Sec<\/strong><\/td>\n1<\/td>\n2\/\u221a3<\/td>\n\u00a0\u221a2<\/td>\n2<\/td>\n\n

\u221e<\/p>\n<\/td>\n<\/tr>\n

Cot<\/strong><\/td>\n\u221e<\/td>\n\u221a3<\/td>\n1<\/td>\n1\/\u221a3<\/td>\n\n

0<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Trigonometric Ratios Of Some Specific Angles With Examples<\/strong><\/h2>\n

\"\"<\/p>\n

Example 1:<\/strong> \u00a0 \u00a0Evaluate each of the following in the simplest form:
\n(i) sin 60\u00ba cos 30\u00ba + cos 60\u00ba sin 30\u00ba
\n(ii) sin 60\u00ba cos 45\u00ba + cos 60\u00ba sin 45\u00ba
\nSol.\u00a0\u00a0\u00a0\u00a0\u00a0 (i)\u00a0<\/strong>\u00a0sin 60\u00ba cos 30\u00ba + cos 60\u00ba sin 30\u00ba
\n\\(=\\frac{\\sqrt{3}}{2}\\times \\frac{\\sqrt{3}}{2}+\\frac{1}{2}\\times \\frac{1}{2}=\\frac{3}{4}+\\frac{1}{4}=1\\)
\n(ii)\u00a0<\/strong> sin 60\u00ba cos 45\u00ba + cos 60\u00ba sin 45\u00ba
\n\\( =\\frac{\\sqrt{3}}{2}\\times \\frac{1}{\\sqrt{2}}+\\frac{1}{2}\\times \\frac{1}{\\sqrt{2}} \\)
\n\\( =\\frac{\\sqrt{3}}{2\\sqrt{2}}+\\frac{1}{2\\sqrt{2}}=\\frac{\\sqrt{3}+1}{2\\sqrt{2}} \\)<\/p>\n

Example 2:<\/strong>\u00a0 \u00a0 \u00a0Evaluate the following expression:
\n(i) tan 60\u00ba cosec2<\/sup> 45\u00ba + sec2<\/sup> 60\u00ba tan 45\u00ba
\n(ii) 4cot2<\/sup> 45\u00ba \u2013 sec2<\/sup> 60\u00ba + sin2<\/sup> 60\u00ba + cos2<\/sup> 90\u00ba.
\nSol. \u00a0 \u00a0\u00a0\u00a0(i)<\/strong>\u00a0 tan 60\u00ba cosec2<\/sup> 45\u00ba + sec2<\/sup> 60\u00ba tan 45\u00ba
\n= tan 60\u00ba (cosec 45\u00ba)2<\/sup> + (sec 60\u00ba)2<\/sup> tan 45\u00ba
\n=\u00a0\u221a3\u00a0\u00d7 (\u221a2)2<\/sup> + (2)2<\/sup>\u00a0\u00d7 1
\n= \u221a3\u00a0\u00a0\u00d7 2 + 4 = 4 + 2\u00a0\u221a3
\n(ii)<\/strong>\u00a0 4cot2<\/sup> 45\u00ba \u2013 sec2<\/sup> 60\u00ba + sin2<\/sup> 60\u00ba + cos2<\/sup> 90\u00ba
\n= 4(cot 45\u00ba)2<\/sup> \u2013 (sec 60\u00ba)2<\/sup> + (sin 60\u00ba)2<\/sup> + (cos 90\u00ba)2<\/sup>
\n= 4 \u00d7 (1)2<\/sup> \u2013 (2)2<\/sup> + (\u221a3\/2)2\u00a0<\/sup>+ 0
\n= 4 \u2013 4 + 3\/4 + 0 = 3\/4<\/p>\n