document.write( "Question 1204118: If tan(x) = −40/9 and x is in quadrant IV, with 0° ≤ x < 360°, find the exact values of the expressions without solving for x.
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\n" ); document.write( "\n" ); document.write( "(b) cos(x/2)\r
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\n" ); document.write( "\n" ); document.write( "(c) tan(x/2)\r
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Algebra.Com's Answer #840166 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "\"tan%28x%29+=+-40%2F9\"\r
\n" ); document.write( "\n" ); document.write( "\"tan%28x%29+=+sin%28x%29%2Fcos%28x%29\"\r
\n" ); document.write( "\n" ); document.write( "also, \r
\n" ); document.write( "\n" ); document.write( "\"tan%28x%29+=+opp%2Fadj\"\r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x%29=+opp+%2F+hyp+\"\r
\n" ); document.write( "\n" ); document.write( "\"cos+%28x%29+=+adj+%2F+hyp\"\r
\n" ); document.write( "\n" ); document.write( "then \"opp%2Fadj=+-40%2F9+\"=> \"opp=-40\", \"adj=9\"\r
\n" ); document.write( "\n" ); document.write( "=> \"hyp=sqrt%28%28-40%29%5E2%2B9%5E2%29=41\"\r
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\n" ); document.write( "\n" ); document.write( "then \r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x%29=+-40%2F+41\"\r
\n" ); document.write( "\n" ); document.write( "\"cos+%28x%29+=+9+%2F+41+\"\r
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\n" ); document.write( "\n" ); document.write( "(a)\r
\n" ); document.write( "\n" ); document.write( "\"sin%28x%2F2%29\"\r
\n" ); document.write( "\n" ); document.write( "using Half Angle Formulas\r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x%2F2%29+=sqrt+%28+%281+-+cos%28x%29%29+%2F+2+%29\"\r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x%2F2%29+=+%28+%281+-%289+%2F+41%29%29+%2F+2+%29\"\r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x%2F2%29+=+sqrt+%28+16%2F41+%29\"\r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x%2F2%29+=++4%2Fsqrt+%28+41+%29\" or \"sin+%28x%2F2%29+=++-+4%2Fsqrt+%28+41+%29\"\r
\n" ); document.write( "\n" ); document.write( "sin is negative in Q IV\r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x%2F2%29+=+-+4%2Fsqrt+%28+41+%29\"\r
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\n" ); document.write( "\n" ); document.write( "(b)\r
\n" ); document.write( "\n" ); document.write( "\"cos%28x%2F2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"cos+%28x%2F2%29+=+sqrt+%28+%281+%2B+%289+%2F+41%29%29+%2F+2+%29\"
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\n" ); document.write( "\"cos+%28x%2F2%29+=+sqrt+%28+%2850%2F41%29+%2F+2+%29+\"\r
\n" ); document.write( "\n" ); document.write( "\"cos+%28x%2F2%29+=+sqrt+%28+25%2F41+%29+\"\r
\n" ); document.write( "\n" ); document.write( "\"cos+%28x%2F2%29+=+5%2Fsqrt%2841%29\"...cos is positive in Q IV\r
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\n" ); document.write( "\n" ); document.write( "\"tan%28x%2F2%29=-%284%2Fsqrt+%28+41+%29%29%2F%285%2F+sqrt%2841%29%29=-4%2F5\"\r
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