document.write( "Question 1196149: Find the exact value of x for which 4cosh(x) - e^-(x) = 3
\n" ); document.write( "Find the exact value of cosh^-ยน(3) - sinh^-1(2)
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Algebra.Com's Answer #828869 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
\"4cosh%28x%29+-+e%5E%28-x%29+=+3\"............................use identity \"cosh%28x%29+=e%5E%28-x%29%2F2+%2B+e%5Ex%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"4%28e%5E%28-x%29%2F2+%2B+e%5Ex%2F2%29-+e%5E%28-x%29+=+3\"\r
\n" ); document.write( "\n" ); document.write( "\"2e%5E%28-x%29+%2B+2+e%5Ex-e%5E%28-x%29+=3\"\r
\n" ); document.write( "\n" ); document.write( "\"+e%5E%28-x%29+%2B+2e%5Ex+=3\"\r
\n" ); document.write( "\n" ); document.write( "\"e%5E%28-x%29+%282+e%5E%282+x%29+%2B+1%29+=3\"\r
\n" ); document.write( "\n" ); document.write( "\"2e%5E%282+x%29+%2B+1=3%2Fe%5E%28-x%29+\"\r
\n" ); document.write( "\n" ); document.write( "\"2e%5E%282x%29+%2B+1=3e%5Ex\"\r
\n" ); document.write( "\n" ); document.write( "\"2e%5E%282x%29+-3e%5Ex%2B1=0\"\r
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\n" ); document.write( "\n" ); document.write( "Rewrite the equation with: \"e%5Ex=u\"\r
\n" ); document.write( "\n" ); document.write( "\"2u%5E2-3u=-1\"\r
\n" ); document.write( "\n" ); document.write( "\"2u%5E2-3u%2B1=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%282u+-+1%29%28u+-+1%29=0\"\r
\n" ); document.write( "\n" ); document.write( "solutions for \"u\":\r
\n" ); document.write( "\n" ); document.write( "if \"%282+u+-+1%29+=0+\"=>\"+2u=1\" =>\"u=1%2F2\"\r
\n" ); document.write( "\n" ); document.write( "if \"+%28u+-+1%29=0\" =>\"u=1\"\r
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\n" ); document.write( "\n" ); document.write( "Substitute back \"u=e%5Ex\", solve for\"+x\"\r
\n" ); document.write( "\n" ); document.write( "\"u=1%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"e%5Ex=1%2F2+\"....take natural log of both sides\r
\n" ); document.write( "\n" ); document.write( "\"ln%28e%5Ex%29=ln%281%2F2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"+x%2Aln%28e%29=ln%281%2F2%29\"\r
\n" ); document.write( "\n" ); document.write( "\"x%2A1=ln%281%29-ln%282%29\"\r
\n" ); document.write( "\n" ); document.write( "\"x=0-ln%282%29\"\r
\n" ); document.write( "\n" ); document.write( "\"x+=+-ln%282%29\"\r
\n" ); document.write( "\n" ); document.write( "or\r
\n" ); document.write( "\n" ); document.write( "\"u=1\"\r
\n" ); document.write( "\n" ); document.write( "\"e%5Ex=1\"\r
\n" ); document.write( "\n" ); document.write( "\"ln%28e%5Ex%29=ln%281%29\"\r
\n" ); document.write( "\n" ); document.write( "\"x%2Aln%28e%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"x%2A1=0\"\r
\n" ); document.write( "\n" ); document.write( "\"x=0\"\r
\n" ); document.write( "\n" ); document.write( "verify solutions:\r
\n" ); document.write( "\n" ); document.write( "\"4cosh%28-ln%282%29%29+-+e%5E%28-%28-ln%282%29%29%29+=+3\"\r
\n" ); document.write( "\n" ); document.write( "\"4%285%2F4%29+-+2%29+=+3\"\r
\n" ); document.write( "\n" ); document.write( "\"5+-+2%29+=+3\"\r
\n" ); document.write( "\n" ); document.write( "\"3%29+=+3\" => true\r
\n" ); document.write( "\n" ); document.write( "or\r
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\n" ); document.write( "\n" ); document.write( "\"4cosh%280%29+-+e%5E%28-0%29+=+3\"
\n" ); document.write( "\"4%281%29+-+1+=+3\"
\n" ); document.write( "\"3=+3\"\r
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\n" ); document.write( "\n" ); document.write( "\"cosh%5E-1%283%29+-+sinh%5E-1%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "Use the following identities: \r
\n" ); document.write( "\n" ); document.write( "\"sinh%5E-1%28x%29=ln%28sqrt%281%2Bx%5E2%29%2Bx%29\"
\n" ); document.write( "\"cosh%5E-1%28x%29=ln%28sqrt%28-1%2Bx%5E2%29%2Bx%29\"\r
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\n" ); document.write( "\n" ); document.write( "so we have\r
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\n" ); document.write( "\n" ); document.write( "\"ln%28sqrt%28-1%2B3%5E2%29%2B3%29-+ln%28sqrt%281%2B2%5E2%29%2B2%29\"\r
\n" ); document.write( "\n" ); document.write( "=\"ln%282sqrt%282%29+%2B+3%29-+ln+%28sqrt%285%29+%2B+2%29\" \r
\n" ); document.write( "\n" ); document.write( "=\"ln%28%282sqrt%282%29+%2B+3%29%2F%28sqrt%285%29+%2B+2%29%29+\"-> exact solution\r
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