document.write( "Question 1030293: The population P(t) of a British Columbian town is modelled by the function P(t)=2t^2+80t+4000. Note: t=0 corresponds to the year 2000.When will the population double its current total? Explain how you got your answer. \n" ); document.write( "

Algebra.Com's Answer #645181 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+P%28t%29+=+2t%5E2+%2B+80t+%2B+4000+\"$
\n" ); document.write( " $\"+t+=+0+\"$
\n" ); document.write( " $\"+P%280%29+=+2%2A0%5E2+%2B+80%2A0+%2B+4000+\"$
\n" ); document.write( " $\"+P%280%29+=+4000+\"$
\n" ); document.write( " $\"+2%2A4000+=+8000+\"$
\n" ); document.write( "-------------------
\n" ); document.write( "When does the population = $\"+8000+\"$ ?
\n" ); document.write( " $\"+P%28t%29+=+8000+\"$
\n" ); document.write( " $\"+8000+=+2t%5E2+%2B+80t+%2B+4000+\"$
\n" ); document.write( " $\"+2t%5E2+%2B+80t+=+4000+\"$
\n" ); document.write( " $\"+t%5E2+%2B+40t+=+2000+\"$
\n" ); document.write( "Complete the square
\n" ); document.write( " $\"+t%5E2+%2B+40t+%2B+%28+40%2F2+%29%5E2+=+2000+%2B+%28+40%2F2+%29%5E2+\"$
\n" ); document.write( " $\"+t%5E2+%2B+40t+%2B+400+=+2000+%2B+400+\"$
\n" ); document.write( " $\"+%28+t+%2B+20+%29%5E2+=+2400+\"$
\n" ); document.write( " $\"+t+%2B+20+=+10%2Asqrt%2824%29+\"$
\n" ); document.write( " $\"+t+=+10%2A4.899+-+20+\"$
\n" ); document.write( " $\"+t+=+48.99+-+20+\"$
\n" ); document.write( " $\"+t+=+29+\"$
\n" ); document.write( "Population will be double in 2029
\n" ); document.write( "---------------------------
\n" ); document.write( "check:
\n" ); document.write( " $\"+8000+=+2t%5E2+%2B+80t+%2B+4000+\"$
\n" ); document.write( " $\"+8000+=+2%2A29%5E2+%2B+80%2A29+%2B+4000+\"$
\n" ); document.write( " $\"+8000+=+1682+%2B+2320+%2B+4000+\"$
\n" ); document.write( " $\"+4000+=+4002+\"$
\n" ); document.write( "Error due to rounding off?
\n" ); document.write( "I think so \n" ); document.write( "

\n" );