document.write( "Question 1099289: Find f(x) given that
\n" ); document.write( "f'(x) = x^3 − 2√x, f(1) = 4
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Algebra.Com's Answer #713721 by KMST(5328)\"\" \"About 
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The derivative of a sum of functions is the sum of the derivatives,
\n" ); document.write( "so the same applies to antiderivatives,
\n" ); document.write( "So to find a function with \"x%5E3-2sqrt%28x%29\" for a derivative,
\n" ); document.write( "we need to find what function has for derivative \"x%5E3\" ,
\n" ); document.write( "and what function has for derivative \"sqrt%28x%29=x%5E%221+%2F+2%22\" .
\n" ); document.write( "We also know that if we find a function with \"x%5E3-2sqrt%28x%29\" for a derivative,
\n" ); document.write( "adding any constant \"C\" , we get another function with the same derivative.
\n" ); document.write( "We will use \"f%281%29=4\" to figure out what constant to add.
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\n" ); document.write( "We know about derivatives of polynomials.
\n" ); document.write( "For any exponent \"r\" (integer or not, as long as \"r%3C%3E-1\" ),
\n" ); document.write( "if \"g%28x%29=x%5E%28r%2B1%29%2F%28r%2B1%29\" , \"%22g+%27+%28+x+%29%22=x%5Er\" ,
\n" ); document.write( "and that lets us figure out the antiderivative of any \"x%5Er\" ,
\n" ); document.write( "except \"x%5E%28-1%29=1%2Fx\" .
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\n" ); document.write( "So, the antiderivative of \"x%5E3\" is \"x%5E4%2F4\" ;
\n" ); document.write( "and the antiderivative of \"sqrt%28x%29=x%5E%221+%2F+2%22\" is \"x%5E%223+%2F+2%22%2F%223+%2F+2%22=%282%2F3%29x%5E%223+%2F+2%22=2x%5E%223+%2F+2%22%2F3\" .
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\n" ); document.write( "So, we can see that \"f%28x%29=x%5E4%2F4-2%282x%5E%223+%2F+2%22%2F3%29%2BC=x%5E4%2F4-4x%5E%223+%2F+2%22%2F3%2BC\"
\n" ); document.write( "for some constant \"C\" .
\n" ); document.write( "Then, \"f%281%29=1%2F4-4%2F3%2BC\" .
\n" ); document.write( "If \"f%281%29=4\" ,
\n" ); document.write( "\"1%2F4-4%2F3%2BC=4\"
\n" ); document.write( "\"C=4%2B4%2F3-1%2F4\"
\n" ); document.write( "\"C=61%2F12\" ,
\n" ); document.write( "and \"highlight%28f%28x%29=x%5E4%2F4-4x%5E%223%2F2%22%2F3%2B61%2F12%29\"
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