# Thread: population growth question using a symetric difference quotient

1. ## population growth question using a symetric difference quotient

If the symetric difference quotient is given as: (P'(t)= P(t+10)-P(t-10)/20)
Given the info below, how would I compute this equation? I am a little lost and getting a bit frustrated... I am not sure what to use for (P'(t)... Any help would be greatly appreciated...

Date population at t time in years after 1790
1790 3.9 t=0
1800 5.3 t=10
1810 7.2 t=20
1820 9.6 t=30
1830 12.9 t=40

2. Originally Posted by bemidjibasser
If the symetric difference quotient is given as: (P'(t)= P(t+10)-P(t-10)/20)
Given the info below, how would I compute this equation? I am a little lost and getting a bit frustrated... I am not sure what to use for (P'(t)... Any help would be greatly appreciated...

Code:
Date         population at t      time in years after 1790
1790             3.9                      t=0
1800             5.3                      t=10
1810             7.2                      t=20
1820             9.6                      t=30
1830            12.9                      t=40
$P'(10)=\dfrac{P(20)-P(0)}{20}=\dfrac{7.2-3.9}{20}$

$P'(20)=\dfrac{P(30)-P(10)}{20}=\dfrac{9.6-5.3}{20}$

etc

CB

3. Thanks CB! Much appreciated!