document.write( "Question 1168592: cos(u) = − 4/5
\n" ); document.write( ", 𝜋/2 < u < 𝜋
\n" ); document.write( "find sin(2u)
\n" ); document.write( "cos(2u)
\n" ); document.write( "tan(2u) \n" ); document.write( "
Algebra.Com's Answer #793185 by ikleyn(52788)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "Use the formulas for trigonometric functions of double argument.\r
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\n" ); document.write( "\n" ); document.write( "For these formulas,  see the lessons\r
\n" ); document.write( "\n" ); document.write( "    - FORMULAS FOR TRIGONOMETRIC FUNCTIONS \r
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\n" ); document.write( "\n" ); document.write( "    - Trigonometric functions of multiply argument - Examples \r
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