document.write( "Question 147784: Find the domain of g(x)=ln(x+4)? I am not sure what to do for this question with the ln? Help? \n" ); document.write( "
Algebra.Com's Answer #108167 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
note: ln is a logarithm where \"ln%28x%29=log%28e%2C%28x%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"ln%28x%2B4%29\" Start with the given expression\r
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\n" ); document.write( "\n" ); document.write( "Remember you cannot take the natural log of zero or of a negative value. So that means the argument \"x%2B4\" must be greater than zero (i.e. the argument must be positive)\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B4%3E0\" Set the inner expression greater than zero\r
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\n" ); document.write( "\n" ); document.write( "\"x%3E0-4\"Subtract 4 from both sides\r
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\n" ); document.write( "\n" ); document.write( "\"x%3E-4\" Combine like terms on the right side\r
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\n" ); document.write( "\n" ); document.write( "So that means x must be greater than \"-4\" in order for x to be in the domain\r
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\n" ); document.write( "\n" ); document.write( "So the domain in set-builder notation is\r
\n" ); document.write( "\n" ); document.write( "-4\right}}\">\r
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\n" ); document.write( "\n" ); document.write( "So here is the domain in interval notation: \r
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\n" ); document.write( "\n" ); document.write( "Notice if we graph \"y=ln%28x%2B4%29\", we get\r
\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+ln%28x%2B4%29%29+\" notice how the graph never crosses the line \"x=-4\". So this graphically verifies our answer.\r
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\n" ); document.write( "\n" ); document.write( "and we can see that x must be greater than \"-4\" in order to lie on the graph
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