{"id":9175,"date":"2021-12-31T23:59:51","date_gmt":"2021-12-31T18:29:51","guid":{"rendered":"https:\/\/mathemerize.com\/?p=9175"},"modified":"2022-01-01T00:32:15","modified_gmt":"2021-12-31T19:02:15","slug":"prove-that-sin90-theta-costheta","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/prove-that-sin90-theta-costheta\/","title":{"rendered":"Prove that \\(Sin(90 – \\theta)\\) = \\(Cos\\theta\\)."},"content":{"rendered":"
Draw a right angled triangle ABC right angled at B.<\/p>\n
Let \\(\\angle\\) A = \\(\\theta\\), then \\(\\angle\\) C = 90 – \\(\\theta\\)<\/p>\n
cos A = \\(cos\\theta\\) = \\(AB\\over AC\\) ……..(1)<\/p>\n
sin C = \\(sin(90 – \\theta)\\) = \\(AB\\over AC\\) ……..(2)<\/p>\n
From (1) and (2), we have<\/p>\n
\\(sin(90 – \\theta)\\) = \\(cos\\theta\\)<\/p>\n","protected":false},"excerpt":{"rendered":"
Solution : Draw a right angled triangle ABC right angled at B. Let \\(\\angle\\) A = \\(\\theta\\), then \\(\\angle\\) C = 90 – \\(\\theta\\) cos A = \\(cos\\theta\\) = \\(AB\\over AC\\) ……..(1) sin C = \\(sin(90 – \\theta)\\) = \\(AB\\over AC\\) …<\/p>\n