document.write( "Question 1072353: Solve sin (2x) + cos (2x) = 0 \n" ); document.write( "
Algebra.Com's Answer #687300 by ikleyn(52781)\"\" \"About 
You can put this solution on YOUR website!
.
\n" ); document.write( "Solve sin (2x) + cos (2x) = 0
\n" ); document.write( "~~~~~~~~~~~~~~~~~~~\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\r\n" );
document.write( "sin (2x) + cos (2x) = 0  --->  sin(2x) = - cos(2x)  --->  tan(2x) = -1  --->  \r\n" );
document.write( "\r\n" );
document.write( "2x = \"3pi%2F4\"   and/or  2x = \"7pi%2F4\".\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "1.  If 2x = \"3pi%2F4\" then there are two answers for x:\r\n" );
document.write( "\r\n" );
document.write( "    a)  x = \"3pi%2F8\"  and  x = \"11pi%2F8\".\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "2.  If 2x = \"7pi%2F4\" then there are two answers for x:\r\n" );
document.write( "\r\n" );
document.write( "    a)  x = \"7pi%2F8\"  and  x = \"15pi%2F8\".\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Answer.  There are 4 solutions:\r\n" );
document.write( "\r\n" );
document.write( "         x = \"3pi%2F8\" ;  x = \"11pi%2F8\";  x = \"7pi%2F8\";  x = \"15pi%2F8\".\r\n" );
document.write( "
\r
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Plot y = sin (2x) + cos (2x)\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "To see more examples of solved trigonometry equations with detailed solutions, 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( "    - OVERVIEW of lessons on calculating trig functions and solving trig equations\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
\n" ); document.write( "
\n" ); document.write( "
\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
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic \"Trigonometry: Solved problems\". \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The solution by Alan is wrong.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );