document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=761723>Question 761723</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 7sin^2x+cos^2x=4 then cosx= </SPAN>\n" );
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document.write( "7sin^2x + cos^2x = 4\r<BR>\n" );
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document.write( "Split the 7 on the left hand side as 6 and 1\r<BR>\n" );
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document.write( "6sin^2x + sin^2x + cos^2x = 4  \r<BR>\n" );
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document.write( "Since sin^2x + cos^2x = 1\r<BR>\n" );
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document.write( "6sin^2x + 1 = 4\r<BR>\n" );
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document.write( "6sin^2x = 3\r<BR>\n" );
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document.write( "sin^2x = 1/2\r<BR>\n" );
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document.write( "sin x = 1/sqrt(2) or -1/sqrt(2)\r<BR>\n" );
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document.write( "Therefore\r<BR>\n" );
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document.write( "cos x = 1/sqrt(2) or -1/sqrt(2)  (cos x = sqrt (1 - sin^2x)\r<BR>\n" );
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document.write( ":) </SPAN>\n" );
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