document.write( "Question 162729: The functions are f(x)=2x^2+5x+7 and g(x)=x^3 + 2
\n" ); document.write( "The directions say evaluate the following: and identify the domain of each
\n" ); document.write( "(f+g)(x)
\n" ); document.write( "I got x^3+2x^2+5x+9 but I dont know what the domain is.
\n" ); document.write( "

Algebra.Com's Answer #119965 by gonzo(654)\"\" \"About 
You can put this solution on YOUR website!
your request:
\n" ); document.write( "-----
\n" ); document.write( "The functions are f(x)=2x^2+5x+7 and g(x)=x^3 + 2
\n" ); document.write( "The directions say evaluate the following: and identify the domain of each
\n" ); document.write( "(f+g)(x)
\n" ); document.write( "I got x^3+2x^2+5x+9 but I dont know what the domain is.
\n" ); document.write( "-----
\n" ); document.write( "my answer:
\n" ); document.write( "-----
\n" ); document.write( "f+g(x) = f(x) + g(x)
\n" ); document.write( "-----
\n" ); document.write( "you got it right again.
\n" ); document.write( "domain is all x since nothing to make the answer imaginary or cause a division by 0.
\n" ); document.write( "-----
\n" ); document.write( "in general, if the domain is not specified, then the domain is whatever makes the range valid.
\n" ); document.write( "there will be 4 graphs.
\n" ); document.write( "scan down after each one to get the next plus any additional comments.
\n" ); document.write( "-----
\n" ); document.write( "graph of f+g(x) is graph of x^3+2x^2+5x+9 shown below
\n" ); document.write( "\"graph%28800%2C800%2C-9%2C9%2C-1000%2C1000%2Cx%5E3%2B2%2Ax%5E2%2B5%2Ax%2B9%29\"
\n" ); document.write( "-----
\n" ); document.write( "graph of g-f(x) is graph of x^3-2x^2-5x-5 shown below
\n" ); document.write( "\"graph%28800%2C800%2C-9%2C9%2C-600%2C600%2Cx%5E3-2%2Ax%5E2-5%2Ax-5%29\"
\n" ); document.write( "-----
\n" ); document.write( "graph of f*g(x) is graph of x^5 + 5x^4 + 7x^3 + 4x^2 + 10x + 14 shown below
\n" ); document.write( "
\n" ); document.write( "-----
\n" ); document.write( "graph of f/g(x) is graph of (2x^2+5x+7)/(x^3+2) shown below
\n" ); document.write( "\"graph%28800%2C800%2C-9%2C9%2C-10%2C10%2C%282%2Ax%5E2%2B5%2Ax%2B7%29%2F%28x%5E3%2B2%29%29\"
\n" ); document.write( "it appears that the graph is good for all values of x except at \"x+=+%28-2%29%5E%281%2F3%29\" where the value is undefined.
\n" ); document.write( "-----
\n" ); document.write( "as x^3 approaches -2 from the right (x^3 is greater than -2), the graph goes positive in a big way.
\n" ); document.write( "for example:
\n" ); document.write( "if you make x^3 = (-1.9999999999999), which is greater than -2, you'll see that the value of y becomes 3.86114E+13 which is a very large positive number.
\n" ); document.write( "-----
\n" ); document.write( "as x^3 approaches -2 from the left (x^3 is smaller than -2), the graph goes negative in a big way.
\n" ); document.write( "for example:
\n" ); document.write( "if you make x^3 = (-2.0000000000001). which is less than -2, you'll see that the value of y becomes -3.89561E+13 which is a very large negative number.
\n" ); document.write( "-----
\n" ); document.write( "the graph does not appear to be able to show this as the intervals between x values appear to be too small to be captured.\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );