document.write( "Question 403218: Solve equation for all value of ų if ų measure in degrees
\n" ); document.write( "cos2ų+3cosų -1=0 \n" ); document.write( "

Algebra.Com's Answer #285145 by Tatiana_Stebko(1539) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"cos2w%2B3cosw+-1=0\"$
\n" ); document.write( "Use FORMULA $\"cos2w=%28cosw%29%5E2-%28sinw%29%5E2\"$
\n" ); document.write( " $\"cos2w%2B3cosw+-1=0\"$
\n" ); document.write( " $\"%28cosw%29%5E2-%28sinw%29%5E2%2B3cosw-1=0\"$
\n" ); document.write( "Use FORMULA $\"%28sinw%29%5E2=1-%28cosw%29%5E2\"$
\n" ); document.write( " $\"%28cosw%29%5E2-%281-%28cosw%29%5E2%29%2B3cosw-1=0\"$
\n" ); document.write( " $\"%28cosw%29%5E2-1%2B%28cosw%29%5E2%2B3cosw-1=0\"$
\n" ); document.write( " $\"2%28cosw%29%5E2%2B3cosw-2=0\"$
\n" ); document.write( "Let $\"cosw=t\"$ , $\"-1%3C=t%3C=1\"$
\n" ); document.write( " $\"2t%5E2%2B3t-2=0\"$
\n" ); document.write( " $\"t+=+%28-3+%2B-+sqrt%28+3%5E2-4%2A2%2A%28-2%29%29%29%2F%282%2A2%29+\"$
\n" ); document.write( " $\"t+=+%28-3+%2B-+sqrt%28+25%29%29%2F4+\"$
\n" ); document.write( " $\"t+=+%28-3+%2B5%29%2F4+\"$ or $\"t+=+%28-3+-5%29%2F4+\"$
\n" ); document.write( " $\"t+=+1%2F2+\"$ or $\"t+=+-2+\"$ >1
\n" ); document.write( " $\"t+=+1%2F2+\"$ , so $\"cosw=1%2F2\"$ ,
\n" ); document.write( "Use FORMULA if $\"cosw=a\"$ , then w=+-arccos(a)+360k, k is any integer
\n" ); document.write( " $\"cosw=1%2F2\"$
\n" ); document.write( "w=+-arccos(1/2)+360k
\n" ); document.write( "w=+-60+360k, k is any integer \n" ); document.write( "

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