document.write( "Question 1098977: Find all degree solutions. (Enter your answers as a comma-separated list. Let k be any integer.)
\n" ); document.write( "2 cos^2 5θ + 3 cos 5θ + 1 = 0 \n" ); document.write( "
Algebra.Com's Answer #713396 by ikleyn(52847)\"\" \"About 
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document.write( "Introduce new variable x = \"cos%28theta%29\".\r\n" );
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document.write( "Then your equation will take the form\r\n" );
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document.write( "\"2x%5E2+%2B+3x+%2B1\" = 0.\r\n" );
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document.write( "It is a quadratic equation. Apply the quadratic formula to solve it:\r\n" );
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document.write( "\"x%5B1%2C2%5D\" = \"%28-3+%2B-+sqrt%283%5E2+-+4%2A2%2A1%29%29%2F%282%2A2%29\" = \"%28-3+%2B-+1%29%2F4\".\r\n" );
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document.write( "1)  Case 1:  \"x%5B1%5D\" = \"%28-3%2B1%29%2F4\" = \"-1%2F2\"  ====>  \"cos%28theta%29\" = \"-1%2F2\" ====>  \"theta\" = \"2pi%2F3%7D+%2B+2k%2Api%7D%7D++or++%7B%7B%7Btheta\" = \"4pi%2F3%2B2k%2Api\".\r\n" );
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document.write( "2)  Case 2:  \"x%5B2%5D\" = \"%28-3-1%29%2F4\" = -1  ====>  \"theta\" = \"pi\" + \"2k%2Api\".\r\n" );
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document.write( "Answer.  The solutions are  \"2pi%2F3%2B2k%2Api\", \"pi%2B2k%2Api\"  and  \"4pi%2F3%2B2k%2Api\".\r\n" );
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\n" ); document.write( "To see many other solved problems on trigonometry equations and to learn more about this subject, look into the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Solving simple problems on trigonometric equations\r
\n" ); document.write( "\n" ); document.write( "    - Solving typical problems on trigonometric equations\r
\n" ); document.write( "\n" ); document.write( "    - Solving more complicated problems on trigonometric equations\r
\n" ); document.write( "\n" ); document.write( "    - Solving advanced problems on trigonometric equations\r
\n" ); document.write( "\n" ); document.write( "    - Proving Trigonometry identities\r
\n" ); document.write( "\n" ); document.write( "    - OVERVIEW of lessons on calculating trig functions and solving trig equations\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-II in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic  \"Trigonometry: Solved problems\". \r
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\n" ); document.write( "\n" ); document.write( "Save the link to this textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-II
\n" ); document.write( "https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson\r
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