Example 1 : <\/span>Find general solution of (2sinx – cosx)(1 + cosx) = \\(sin^2x\\)<\/p>\n Solution : <\/span>(2sinx – cosx)(1 + cosx) – (1 – \\(cos^2x\\)) = 0 Example 2 : <\/span> Solve : 6 – 10cosx = 3\\(sin^2x\\)<\/p>\n Solution : <\/span>we have, 6 – 10cosx = 3\\(sin^2x\\) Example 3 : <\/span>Solve : cos3x + sin2x – sin4x = 0<\/p>\n Solution : <\/span>we have, cos3x + (sin2x – sin4x) = 0 Practice these given trigonometric equation examples to test your knowledge on concepts of trigonometric equation.<\/p>\n \n <\/div>\n <\/div>\n","protected":false},"excerpt":{"rendered":" Here you will learn some trigonometric equation examples for better understanding of trigonometric equation concepts. Example 1 : Find general solution of (2sinx – cosx)(1 + cosx) = \\(sin^2x\\) Solution : (2sinx – cosx)(1 + cosx) – (1 – \\(cos^2x\\)) = 0 \\(\\therefore\\) (1 + cosx)(2sinx – cosx – 1 + cosx) = 0 …<\/p>\n
\n \\(\\therefore\\) (1 + cosx)(2sinx – cosx – 1 + cosx) = 0
\n \\(\\therefore\\) (1 + cosx)(2sinx – 1) = 0
\n \\(\\implies\\) cosx = -1 or sinx = \\(1\\over 2\\)
\n \\(\\implies\\) cosx = -1 = cos\\(\\pi\\) \\(\\implies\\) x = 2n\\(\\pi\\) + \\(\\pi\\) = (2n+1)\\(\\pi\\), n \\(\\in\\) I\n
\n or sinx = \\(1\\over 2\\) = sin\\(\\pi\\over 6\\) \\(\\implies\\) x = k\\(\\pi + (-1)^k{\\pi\\over 6}\\), k \\(\\in\\) I<\/p>\n
\n\n \n
\n \\(\\therefore\\) 6 – 10cosx = 3 – 3\\(cos^2x\\)
\n \\(\\implies\\) 3\\(cos^2x\\) – 10cosx + 3 = 0
\n \\(\\implies\\) (3cosx-1)(cosx-3) = 0 \\(\\implies\\) cosx = \\(1\\over 3\\) or cosx = 3
\n Since cosx =3 is not possible as -1 \\(\\le\\) cosx \\(\\le\\) 1
\n \\(\\therefore\\) cosx = \\(1\\over 3\\) = cos(\\(cos^{-1}{1\\over 3}\\)) \\(\\implies\\) x = 2n\\(\\pi\\) \\(\\pm\\) \\(cos^{-1}{1\\over 3}\\)<\/p>\n
\n\n \n
\n = cos3x – 2sinx.cos3x = 0
\n \\(\\implies\\) (cos3x)(1 – 2sinx) = 0
\n \\(\\implies\\) cos3x = 0 or sinx = \\(1\\over 2\\)
\n \\(\\implies\\) cos3x = 0 = cos\\(\\pi\\over 2\\) or sinx = \\(1\\over 2\\) = sin\\(\\pi\\over 6\\)
\n \\(\\implies\\) 3x = 2n\\(\\pi\\) \\(\\pm\\) \\(\\pi\\over 2\\) or x = m\\(\\pi\\) + \\({(-1)}^m\\)\\(\\pi\\over 6\\)
\n \\(\\implies\\) x = \\(2n\\pi\\over 3\\) \\(\\pm\\) \\(\\pi\\over 6\\) or x = m\\(\\pi\\) + \\({(-1)}^m\\)\\(\\pi\\over 6\\); (n, m \\(\\in\\) I)\n <\/p>\n
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